Maintaining a library can be exceptionally difficult. As time progresses new demands arise that weren't there when the API was first created. Sometimes simple work arounds can be found to prevent breaking library consumers when they upgrade. Sometimes the changes are no brainers that have no negative affects. Sometimes changes simply aren't made because the potential breaks are simply too risky. Other times the benefits simply outweigh the break and changes are made.

Prism 7.1 is largely the result of changes that the Prism Team has come to realize had to be made. As part of the overall Prism 7.X effort, the team has been working on bringing the API closer together across each platform target where possible. Currently this is perhaps most evident with the introduction of the Prism.Ioc namespace allowing developers to more easily port from one DI Container to another, and even create Prism Modules that are sharable across projects with different DI Containers.

In this release have made some major changes to better unify the API between Xamarin Forms and our ongoing work with Jerry Nixon to bring Template 10 to Prism for UWP. This effort though represented the need to create a binary incompatibility, a need to create some breaking changes, and an opportunity to greatly improve the API for Xamarin Forms developers. So what are the changes? For starters we've migrated most of the Prism.Navigation namespace from Prism.Forms to Prism.Core. After a lot of deliberation we ultimately decided that these changes should not be available to WPF developers as it just doesn't make sense for WPF applications. 

In addition to the binary incompatibility caused by moving the classes from one binary to another, this creates a secondary break in the WPF will NOT be supported for Xamarin Forms developers.

I mentioned that there are breaking changes and some opportunities for improvements as well. The break that you will encounter should be fixable with a simple Find/Replace in your IDE or text editor, as NavigationParameters is now INavigationParameters which changes the method signatures for INavigatingAware, INavigatedAware, INavigationAware, IConfirmNavigation, IConfirmNavigationAsync, and INavigationService. While that may provide you with some unique opportunities for testing, that isn't the exciting change. The change is the return type from INavigationService from a simple Task to Task<INavigationResult>. Why is that so great? Well for one thing if the Navigation failed for some reason you'll have access to a Boolean to more easily execute that logic. It's also great though because until now the NavigationService could make it harder to determine what type of exception may have been thrown. INavigationResult fixes this by returning the actual exception that was thrown allowing you greater control over what to do with it.

var result = await _navigationService.NavigateAsync("BadPage");

if(!result.Success)
{
    await _pageDialogService.DisplayAlertAsync(result.Exception.GetType().Name, result.Exception.Message, "Ok");
}

Perhaps my single favorite improvement in Prism 7.1 for Xamarin Forms developers is the inclusion of the ContainerProvider. This was born out of a desire to be able to declare types such as a TypeConverter that may rely on some service in your application. The ContainerProvider will allow you to declare in XAML, types that do not have a default constructor and inject any of your applications services into that type. 

<?xml version="1.0" encoding="UTF-8" ?>
<ContentPage
    xmlns="http://xamarin.com/schemas/2014/forms"
    xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
    xmlns:prism="clr-namespace:Prism.Ioc;assembly=Prism.Forms"
    xmlns:converters="using:Prism.Forms.Tests.Mocks.Converters"
    Title="{Binding Title}"
    x:Class="Prism.DI.Forms.Tests.Mocks.Views.XamlViewMock">
    <ContentPage.Resources>
        <ResourceDictionary>
            <prism:ContainerProvider x:TypeArguments="converters:MockValueConverter" x:Key="mockValueConverter" />
        </ResourceDictionary>
    </ContentPage.Resources>
    <Entry x:Name="testEntry"
           Text="{Binding Test,Converter={StaticResource mockValueConverter}}" />
</ContentPage>

Unity

Unity has been one of the most popular containers for Prism Developers. I have no doubt that this has a lot to do with the fact that it is the container Brian has used for years, has used in his demos and that was most widely available in the Prism Template Pack. The Unity team has made some major design changes in Unity 5.X. For Prism developers using Unity we have long since had a dependency on the Unity NuGet package. In it's current state, this actually broke Prism.Unity.Forms for netstandard1.0. 

The Unity team has redefined the Unity NuGet package to be an all inclusive package that presents several problems. For Xamarin Forms developers, it introduces references to 6 more assemblies than what you actually need or would use. For WPF developers it creates a secondary, and hidden reference to CommonServiceLocator, as well as the inclusion of 5 more assemblies than what you need or Prism uses. To continue depending on this NuGet package represents an additional issue that it could continue to break Prism developers. To resolve this, Prism 7.1 has changed it's target from Unity to Unity.Container. This change will be unnoticeable to anyone who uses the new PackageReference to include NuGet's in their projects, particularly when you have your dependency on Prism.Unity or Prism.Unity.Forms and not Unity itself. For all other Unity developers, you should uninstall Unity from your projects before upgrading to Prism 7.1.

.NET Standard has really changed the ballgame for .NET Developers. In large part because the entire project system has experienced a revamp. Lately I've found myself really encouraging developers to update their PCL libraries to .NET Standard 2.0. For developers who haven't made the jump it's easy to find yourself saying "no we can't do it". In reality it doesn't take as much effort as you think it does to update your projects. Why should you update your projects though? Well for starters PCL is painful, you lookup how to do something only to find out that it's not supported and sometimes there's no workaround. With .NET Standard the missing API's that lead to weird workarounds is a thing of the past.

Upgrading

Upgrading really isn't as hard as you may think. For starters your csproj is going to start out about as simple as:

<Project Sdk="Microsoft.NET.Sdk" ToolsVersion="15.0">
  <PropertyGroup>
    <TargetFramework>netstandard2.0</TargetFramework>
  </PropertyGroup>
</Project>

Then of course we need to start adding in your dependencies. Now this is where it gets "Hard". It's hard because it means you need some familiarity with your project. You need to know what are the top level dependencies that your project has. For example if you're using Prism there are generally 3 Prism packages you're referencing, Prism.Core, Prism.Forms, and Prism.{Some Container}.Forms. It's only the last one that you actually need to reference in the new project format. You can of course add this from either Visual Studio or Visual Studio Mac or update it manually so that your project file now looks like:

<Project Sdk="Microsoft.NET.Sdk" ToolsVersion="15.0">
  <PropertyGroup>
    <TargetFramework>netstandard2.0</TargetFramework>
  </PropertyGroup>
  <ItemGroup>
    <PackageReference Include="Prism.DryIoc.Forms" Version="7.0.0.396" />
  </ItemGroup>
</Project>

Assuming you wanted to get started with Prism for Xamarin Forms this would be all you would actually need as all three Prism packages are automatically brought in along with Xamarin Forms. Now let's say that you wanted to target a newer version of Xamarin Forms than 2.5.0.122203, such as the 3.0 preview that's now available. You simply need to add a new PackageReference for that version of Xamarin Forms or install it in the IDE's Package Manager.

That may seem too easy, and it is. Of course you need to make some more changes. You'll need to find the packages.config or project.json and delete those files... If you have a standard Properties/AssemblyInfo.cs you'll need to go ahead and send that one to the trash as well. With that your project is upgraded, and you're wondering why you didn't do this sooner....

Multi Targeting

Around 5 years ago I first started trying to Multi-Target. My earliest attempts were pretty bad with a csproj file for each framework I wanted to target, all part of the same solution, and it generally resulted in build errors due to file locks as I had no clue how the build system worked back then. Honestly I've never found much documentation that made it very easy, and while I eventually figured out I could do lots of MSBuild trickery to make it work, and then manually develop a nuspec to pack my library, it was always really painful. The new Project system gives us some real advantages for Mutli-Targeting that make it a real breeze.

I suppose though I should start with why on earth should you multi-target... and when would you want to? If you're a Xamarin developer chances are you want to Multi-Target. Internally and for all of my clients I generally start off with a common library. This is something that is really helpful to give me extensions, and custom controls that I may want to use across all of my apps or components like a Prism Module. A lot of that code is truly portable and I could easily handle it with a simple netstandard2.0 class library. However sometimes I'm implementing Platform Effects and Renderers for my controls that instantly require that I have a native binary for my iOS and Android projects. This is where multi-targeting really becomes very powerful. By Multi-Targeting I maintain a single Project which generates a single binary, native to the platform I need to target. Now if we expand on the basic project structure we saw above and now update our csproj to look like the following we can target both .NET Standard 1.3 & 2.0, along with Android, iOS, Mac, and UWP. It's worth noting that the non .NET Standard targets are really getting a lot of help due to the MSBuild.Sdk.Extras package from Oren Novotny.  

<Project Sdk="Microsoft.NET.Sdk" ToolsVersion="15.0">
  <PropertyGroup>
    <TargetFrameworks></TargetFrameworks>
    <TargetFrameworks Condition=" '$(OS)' == 'Windows_NT' ">netstandard1.3;netstandard2.0;Xamarin.iOS10;Xamarin.Mac2.0;MonoAndroid80;uap10.0.16299</TargetFrameworks>
    <TargetFrameworks Condition=" '$(OS)' != 'Windows_NT' ">netstandard1.3;netstandard2.0;Xamarin.iOS10;Xamarin.Mac2.0;MonoAndroid80</TargetFrameworks>
  </PropertyGroup>
  <ItemGroup>
    <Compile Remove="**/Platform/**/*.cs" />
    <None Include="**/Platform/**/*.cs" />
  </ItemGroup>
  <ItemGroup Condition=" $(TargetFramework.StartsWith('MonoAndroid')) ">
    <None Remove="**/Platform/Droid/**/*.cs" />
    <Compile Include="**/Platform/Droid/**/*.cs" />
  </ItemGroup>
  <ItemGroup Condition=" $(TargetFramework.StartsWith('Xamarin.iOS')) ">
    <None Remove="**/Platform/iOS/**/*.cs" />
    <Compile Include="**/Platform/iOS/**/*.cs" />
  </ItemGroup>
  <ItemGroup Condition=" $(TargetFramework.StartsWith('Xamarin.Mac')) ">
    <None Remove="**/Platform/macOS/**/*.cs" />
    <Compile Include="**/Platform/macOS/**/*.cs" />
  </ItemGroup>
  <ItemGroup Condition=" $(TargetFramework.StartsWith('uap10.0')) ">
    <None Remove="**/Platform/UWP/**/*.cs" />
    <Compile Include="**/Platform/UWP/**/*.cs" />
  </ItemGroup>
  <ItemGroup>
    <PackageReference Include="MSBuild.Sdk.Extras" Version="1.2.2" PrivateAssets="All" />
  </ItemGroup>
  <ItemGroup Condition=" $(TargetFramework.StartsWith('uap10.0')) ">
    <PackageReference Include="Microsoft.NETCore.UniversalWindowsPlatform" Version="6.0.6" />
    <SDKReference Include="WindowsMobile, Version=10.0.16299.0">
      <Name>Windows Mobile Extensions for the UWP</Name>
    </SDKReference>
  </ItemGroup>
  <Import Project="$(MSBuildSDKExtrasTargets)" Condition="Exists('$(MSBuildSDKExtrasTargets)')" />
</Project>

So what's going on here anyway? Well for starters we're establishing some conventions for our code. We are saying that anywhere in our project that we have a folder named Platform we are going to change the inclusion of those files from Compile to None. This means that the IDE will display our code while MSBuild will ignore our code. Then, we start conditionally adding code back in so that when MSBuild is compiling for iOS and it encounters code that has a path that includes Platform/iOS, that code will be added back in for compilation. 

Generating a NuGet

If you're trying to generate a library that you can easily consume in your projects, or if you're trying to make it available for the community at large, these new SDK style projects are make generating a NuGet easier than ever. You just need to worry about what targets you want to compile for, and the NuGet largely takes care of itself with very little that we actually need to add. It's really just a few properties that we need to add to our project. Of course, if you take a look at any of my projects you'll notice a recurring theme, most of my NuGet configurations aren't even in the project file at all. Along the way I've come to realize the power of a file called Directory.build.props. This is a little bit of a magic file. If it exists anywhere from the solution folder to your project folder it will automatically be picked up by MSBuild. 

Looking at a real world example

Prism has more than 15 NuGet packages that have to generated on every build. Honestly for WPF we still use the older style projects which is a painful process, but the rest of the projects all share a lot of common logic.

• If there is a project that isn't a test project we don't want it to Generate a NuGet. 
• The package authors are always going to the members of the Prism Team.
• The source is always located on GitHub in the same repository.
• We always want to provide symbols packages.

Without using the Directory.build.props in our solution directory we would have to replicate this information in every single project file. 

Setting your project up for NuGet Packaging

If you want to pack your project all you really need to do is to add the following Directory.build.props to your project:

<Project>
  <PropertyGroup>
    <Product>$(AssemblyName) ($(TargetFramework))</Product>
    <NeutralLanguage>en</NeutralLanguage>
    <Authors>Your Name Here</Authors>
    <VersionPrefix>1.0.0</VersionPrefix</VersionPrefix>
    <VersionPrefix Condition=" '$(BUILD_BUILDID)' != '' ">$(VersionPrefix).$(BUILD_BUILDID)</VersionPrefix>
    <IS_PREVIEW Condition=" '$(IS_PREVIEW)' == '' ">false</IS_PREVIEW>
    <IS_RELEASE Condition=" '$(IS_RELEASE)' == '' ">false</IS_RELEASE>
    <VersionSuffix>ci</VersionSuffix>
    <VersionSuffix Condition=" $(IS_PREVIEW) ">pre</VersionSuffix>
    <VersionSuffix Condition=" $(IS_RELEASE) "></VersionSuffix>
    <PackageProjectUrl>https://github.com/USER/PROJECT_NAME</PackageProjectUrl>
    <PackageLicenseUrl>https://github.com/USER/PROJECT_NAME/blob/master/LICENSE</PackageLicenseUrl>
    <RepositoryType>git</RepositoryType>
    <RepositoryUrl>https://github.com/USER/PROJECT_NAME</RepositoryUrl>
    <IncludeSymbols>True</IncludeSymbols>
    <IncludeSource>True</IncludeSource>
    <PackageOutputPath>$(MSBuildThisFileDirectory)Artifacts</PackageOutputPath>
    <PackageOutputPath Condition=" '$(BUILD_ARTIFACTSTAGINGDIRECTORY)' != '' ">$(BUILD_ARTIFACTSTAGINGDIRECTORY)</PackageOutputPath>
    <IsTestProject>$(MSBuildProjectName.Contains('Test'))</IsTestProject>
    <GenerateDocumentationFile>!$(IsTestProject)</GenerateDocumentationFile>
    <GeneratePackageOnBuild>!$(IsTestProject)</GeneratePackageOnBuild>
  </PropertyGroup>
</Project>

AppCenter has been touted as this wonderful new service from Microsoft. It's supposed to make it easier to build, test and distribute our apps. While there is a lot I love about AppCenter, the simplification of the Build pipeline over VSTS always seemed to be problematic to me. For years I have had a pet peeve that developers often check things into source control that should never be checked in. Sometimes it's simply a backend URL, other times it could be a Client ID. These sorts of things should never be checked in, and should be injected as part of the Build pipeline. The problem is that when you have only a very simple process in place for creating a new build it opens you up to make these sorts of poor decisions with your code base.

For those who are familiar with AppCenter you may be familiar with the fact that you can add scripts to your projects:

• appcenter-post-clone.sh (Bash for iOS & Android)

#!/usr/bin/env bash

# Example: Clone a required repository
git clone https://github.com/example/SomeProject

# Example: Install App Center CLI
npm install -g appcenter-cli

• appcenter-pre-build.sh (Bash for iOS & Android)

#!/usr/bin/env bash

# Example: Change bundle name of an iOS app for non-production
if [ "$APPCENTER_BRANCH" != "master" ];
then
    plutil -replace CFBundleName -string "\$(PRODUCT_NAME) Beta" $APPCENTER_SOURCE_DIRECTORY/MyApp/Info.plist
fi

• appcenter-post-build.sh (Bash for iOS & Android)

#!/usr/bin/env bash

HOCKEYAPP_API_TOKEN={API_Token}
HOCKEYAPP_APP_ID={APP_ID}

# Example: Upload master branch app binary to HockeyApp using the API
if [ "$APPCENTER_BRANCH" == "master" ];
then
    curl \
    -F "status=2" \
    -F "[email protected]$APPCENTER_OUTPUT_DIRECTORY/MyApps.ipa" \
    -H "X-HockeyAppToken: $HOCKEYAPP_API_TOKEN" \
    https://rink.hockeyapp.net/api/2/apps/$HOCKEYAPP_APP_ID/app_versions/upload
else
    echo "Current branch is $APPCENTER_BRANCH"
fi

Simplifying Builds

While ridiculously powerful in what you can do with these scripts (I've been told you can install pretty much anything you want), this seems like far too much effort. I'll even admit that while I'm quite capable of writing whatever scripts I want, beyond a POC, I have never, and have no plans of writing scripts, to get my projects building on AppCenter. There are some things, that shouldn't require lots of work, just to make builds work from one project to another. This is where the Mobile.BuildTools comes in. The Mobile.BuildTools is an easy to use NuGet package. It simply adds tooling for MSBuild and has no binaries that are injected into your application. Because of this it can be used anywhere that you have MSBuild including Visual Studio, Visual Studio Mac, Visual Studio Code, or any Build Host including AppCenter. I have often referenced it as "DevOps in a box", or at least in a NuGet. I should probably add here, that it's called Mobile.BuildTools not just because you can use it on Mobile Apps. You can use this on literally ANY .NET Project, on ANY Platform supported by MSBuild.

Setting Up Your Application

After installing the NuGet, we can add a JSON file to our PCL or .NET Standard named secrets.json, like the following:

{
  "AppCenter_iOS_Secret": "{Your Secret Here}",
  "AppCenter_Android_Secret": "{Your Secret Here}"
}

Note that I've given it the rather long name here for illustrative purposes and to make it easier to read, but ultimately you can add as many keys as you want with whatever name you want. At build this will then automatically generate a Secrets class in your project's Helpers namespace. This will regenerate on each build, so any changes should be made to the JSON file and not the C# file. You should also add secrets.json and Secrets.cs to your .gitignore. If you're using my template packs, this is already done for you. 

I've gotten the question, what happens when I have some value that isn't a string? That's a fantastic question, and the Mobile.BuildTools has you covered there as well with support for string, int, double, and bool data types.

Protecting Your App Manifest

Sometimes secrets don't limit themselves to some constant value in our App. Sometimes we need to declare something sensitive in either our Info.plist or AndroidManifest.xml. This creates an issue for us as well. We obviously need to be able to test locally, but again we need to ensure we don't check these files in with those sensitive values. The Mobile.BuildTools again have your back. By adding these files to our .gitignore we keep from checking in sensitive values. In truth most of these manifests really aren't all that sensitive. To make it simple though we can simply check in a tokenized version of these manifests. Note that by default tokens should are delimited by double dollar signs before and after the variable name such as $$AppCenterSecret$$.

| - MyProject.sln
| - build/
| - | - AndroidTemplateManifest.xml
| - | - BuildTemplateInfo.plist

Sample BuildTemplateInfo.plist

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
    <key>CFBundleDisplayName</key>
    <string>AppCenter.DemoApp</string>
    <key>CFBundleName</key>
    <string>AppCenter.DemoApp</string>
    <key>CFBundleIdentifier</key>
    <string>com.appcenter.demoapp</string>
    <key>CFBundleShortVersionString</key>
    <string>1.0</string>
    <key>CFBundleVersion</key>
    <string>1.0</string>
    <key>LSRequiresIPhoneOS</key>
    <true/>
    <key>MinimumOSVersion</key>
    <string>8.0</string>
    <key>UIDeviceFamily</key>
    <array>
        <integer>1</integer>
        <integer>2</integer>
    </array>
    <key>UILaunchStoryboardName</key>
    <string>LaunchScreen</string>
    <key>UIRequiredDeviceCapabilities</key>
    <array>
        <string>armv7</string>
    </array>
    <key>UISupportedInterfaceOrientations</key>
    <array>
        <string>UIInterfaceOrientationPortrait</string>
        <string>UIInterfaceOrientationLandscapeLeft</string>
        <string>UIInterfaceOrientationLandscapeRight</string>
    </array>
    <key>UISupportedInterfaceOrientations~ipad</key>
    <array>
        <string>UIInterfaceOrientationPortrait</string>
        <string>UIInterfaceOrientationPortraitUpsideDown</string>
        <string>UIInterfaceOrientationLandscapeLeft</string>
        <string>UIInterfaceOrientationLandscapeRight</string>
    </array>
    <key>XSAppIconAssets</key>
    <string>Assets.xcassets/AppIcon.appiconset</string>
    <key>CFBundleURLTypes</key>
    <array>
        <dict>
            <key>CFBundleURLSchemes</key>
            <array>
                <string>appcenter-$$AppCenterSecret$$</string>
            </array>
        </dict>
    </array>
</dict>
</plist>

Setting Up AppCenter For Builds

Keep in mind here that our code now relies on a class called Secrets with several constants that exist nowhere in our codebase, and we have an iOS project without an Info.plist and an Android project without the AndroidManifest.xml... AppCenter offers us the ability to easily add Environment Variables. And this is where the build tools will be able to pick up what we need. 

The Mobile.BuildTools are highly configurable based on preferences, but by default a common project type such as PCL or .NET Standard library will look for any variables prefixed with Secret_, while platform targets look for this with their name like iOSSecret_ or DroidSecret_. Setting any of these in the build will generate a secrets.json and resulting Secrets class in the target project. I did of course say that we have a tokenized version of our manifests which have both the wrong name and tokens that need to be replaced. Just like with the secrets though the variables need to be prefixed, however the default prefix for this is simply Manifest_.  

Get Started

To get started install the Mobile.BuildTools into your project. These tools are free and open source, with documentation on additional configuration options that can be found on GitHub. If you have any issues or have a great idea that you would like to see added to the tools open an issue.

Want to see more? Be sure to check out the demo app.

Several Months ago I set out to make some of the most powerful Xamarin Project Templates. I've gotten a lot of feedback on the Prism QuickStart Templates and how they have accelerated Mobile Development for Developers. One of the features that has really caught the attention of so many developers is the Application Secrets generation. Mobile Apps so often have sensitive information such as Client Id's, or builds that require some minor changes such as pointing to one backend API for Development, another for Staging, and yet another for Production. The custom tasks that have been included in the QuickStart Templates have been helping developers for months to more easily handle these tasks.

Over time as I've made changes and improvements I've come to realize that it has left existing projects in a state where they have been unable to take advantage of changes. There has also been the fact that while they have been tied exclusively to the Prism QuickStart Templates though there is nothing about these great Build Tasks that are tied in any way to Prism. These wonderful Build Props and Build Targets have been separated out into an easy to install NuGet. Since this only contains build props and targets it adds nothing to the size of assemblies, but it does make your DevOps a whole lot easier.

Build Props

While many developers may not currently be utilizing many Build Props, the Mobile.BuildTools adds a number of properties that help you determine what type of project is building and on what type of Host. This could for example better assist you in developing Build tasks that only execute on Windows or Mac, determine if PowerShell is installed. You can also easily determine what platform the project is. We'll take a look at an example below.

Build Secrets

Modern apps are full of Client Id's, and Secrets that it can be maddening for Security. After all how do you develop an app that requires this type of sensitive information without compromising security by checking code into Source Control that contains our Id's and Secrets? Better yet how can we develop better CI/CD pipelines that are customized for an environment such as Development, Staging, or Production? This is where the Secrets Task shines. By simply including a file named secrets.json in your project root, the Secrets Task will generate a Secrets class for you. This enables you to ignore both the Secrets.cs and secrets.json files in your .gitignore. This frees your Build Server to generate your secrets.json and the rest is handled for you.

Templating Project Manifests

Sometimes our DevOps process requires having flexibility across our app manifests. While I am sure there are a multitude of reasons for why you might have this requirement the two most common use cases I see are:

• I am developing an Application that must be tweaked for multiple customers and deployed to the App Store for each (i.e. a Banking App)
• My application requires a setting in my manifest that exposes a Client ID or some other sensitive piece of information (i.e. I am using the Microsoft.Identity.Client for Azure Active Directory)

This is another area where the Mobile.BuildTools really shines by allowing you to include safe to check in Manifest Templates which will then be appropriately copied to your iOS or Android project. As I mentioned before this is just a sample of how the Build Props can better assist your DevOps. Each Copy task is restricted so that the AndroidManifest.xml is only copied when IsAndroidProject is true, and the Info.plist is only copied when IsiOSProject is true. 

FAQ

Q. What happens if I don't have a secrets.json included in my Project?
A. Nothing. The Task will safely execute, not having found a secrets.json file and will finish without creating anything.

Q. Can I name secrets.json something else?
A. Yes, it is a configurable Property. You can add JsonSecretsFileName to the PropertyGroup of your Project with the file name it should look for.

Q. Can you have secrets in more than one Project?
A. Yes, you can have secrets in as many projects as you want. Again the Task will only generate the Secrets class if you have a secrets.json present.

Q. The idea of a Tokenized Manifest sounds cool, but I don't need it. Can I still use the BuildTools?
A. Yes! As long as the AndroidManifest.xml or Info.plist is present when the Build is started it will not copy them over. Otherwise it would get really annoying during development to get some Tokenized manifest constantly undoing your changes.

Q. How do I find out more about setting up the Manifest Templates? Is is customizable?
A. You can find out more on GitHub. You can override the default variables to change the location of the templates, and even the Template Names. 

Q. Am I able to swap out the appxmanifest on UWP? 
A. UWP is not currently handled by default, however you can easily add support by adding ManifestDestinationPath and TemplateManifestPath to the PropertyGroup in your UWP Project.

Q. Does it work on with Visual Studio and Visual Studio for Mac?
A. Yes it work on both Mac and Windows. As part of migrating this out of the templates, the tasks have been upgraded to compiled tasks meaning it works with MSBuild without any additional requirement for PowerShell.

Getting Started

For existing QuickStart Template Projects, you will need to delete the Directory.build.props and Directory.build.targets. You can also delete the PowerShell scripts. To get started, simply install the Mobile.BuildTools NuGet into any project you need to generate App Secrets or an iOS/Android project that you want to be able to swap out the Manifest for. 

So much goes into developing a Xamarin Forms application, and Prism for Xamarin Forms is continuing to make your mobile development a little easier. Today we released Preview 3 for Prism 7, and a lot has happened since I published the Sneak Peak and the changes to Autofac.

Navigation

One of the big things developers love about Prism is Deep Linking like "NavigationPage/ViewA/ViewB/ViewC". Unfortunately this also exposes a bug in Xamarin Forms which the Xamarin team hasn't fixed. The result has been that the Title displayed in the NavigationPage is for ViewA rather than ViewC. Prism 7 has finally fixed this issue so that deep linking can still occur properly.

A long awaited feature is Relative Navigation. We see this all the time in web development, and beginning with preview 3 you can now simplify our Navigation like "../SomePage". This will both pop the current page and add SomePage to the Navigation Stack. Keep in mind that this feature will only work within the context of a NavigationPage. 

Another long await feature has been the ability to simply go back to the root. Prism's Navigation Service now includes a GoBackToRootAsync extension that will support this exact use case. 

TabbedPages

Prism 7 has a lot of fixes to make working with TabbedPages a joy. In past versions of Prism we've had to both explicitly set the ViewModelLocator.AutowireViewModel property on any pages that will be children of a TabbedPage, and we've had to create a TabbedPage that explicitly sets the tabs.

<?xml version="1.0" encoding="UTF-8"?>
<TabbedPage xmlns="http://xamarin.com/schemas/2014/forms"
            xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
            xmlns:local="clr-namespace:AwesomeApp.Views;assembly=AwesomeApp"
            x:Class="AwesomeApp.Views.MyTabbedPage">

    <local:ViewA />
    <local:ViewB />
    <local:ViewC />

</TabbedPage>

Beginning with Prism 7 you can now simply register the Xamarin Forms TabbedPage for Navigation and simply navigate like "TabbedPage?createTab=ViewA&createTab=ViewB&createTab=ViewC". But it doesn't stop there. There are times that we want to use a NavigationPage for a particular tab. We can now easily do this by adding the pipe character and navigating like: "TabbedPage?createTab=ViewA&createTab=NavigationPage|ViewB&createTab=ViewC". Best of all is that the NavigationService now better handles the children so that whether you have a traditional TabbedPage like above or one generated from the querytstring your pages will be automatically get the ViewModelLocator.AutowireViewModel set, and any Prism Behaviors will also automatically be set.

There has also been a major breaking change for selecting the active tab. In previous versions of Prism for Xamarin Forms you could set the active tab by adding the tab to select as the next Uri segment "MyTabbedPage/ViewB". This has been changed in preference of a querystring parameter like "TabbedPage?selectedTab=ViewB". Note that for those who are concerned about magic strings, we've got you covered as this is all based on the constants in KnownNavigationParameters. Putting this all together you can now navigate like:

_navigationService.NavigateAsync($"TabbedPage?{KnownNavigationParameters.CreateTab}=ViewA&{KnownNavigationParameters.CreateTab}=ViewB&{KnownNavigationParameters.CreateTab}=ViewC&{KnownNavigationParameters.SelectedTab}=ViewC");

Lifecycle

IActiveAware has been around Prism for some time but has only had limited support to handle when a page becomes the current page inside of a TabbedPage or CarouselPage. A new interface has been added to Prism.Forms called IPageLifecycleAware. This is handled through a Behavior added to every page by the NavigationService which will allow you to respond to the Appearing and Disappearing events.

Sticking with being Lifecycle aware, preview 3 has introduced a breaking change from earlier previews with IApplicationLifecycle to IApplicationLifecycleAware. While there hasn't been any actual changes to the way it works, it does better fit the naming conventions in Prism.

Modularity

Modularity has long been a core concept in Prism. Modularity has gotten a whole lot nicer in Prism 7 with a few fixes. To start with IModuleCatalog was fixed to properly return IModuleCatalog rather than ModuleCatalog when adding a Module. One of the problems with adding Modules in previous versions has been the verbosity that was required:

ModuleCatalog.AddModule(new ModuleInfo(nameof(SomeModule), typeof(SomeModule), InitializationMode.WhenAvailable));

This can now be simplified like:

// Basic Registration
ModuleCatalog.AddModule<SomeModule>();

There are of course some overloads to specify either the name or Initialization Mode. We have also added extensions to better determine whether a Module has been added to the ModuleCatalog and what the ModuleState is.

I'm all about working with XAML in my Xamarin Forms apps. Developers coming from a WPF background have been used to some great tooling for visually styling their XAML for years. Xamarin Forms of course isn't so cut and dry for the obvious reason that we're dealing with an Abstraction of the UI. Chances are you've probably heard about Xamarin's Live Player. To be honest I think it's a cute idea, but really lacks what you need to be most productive. 

Naturally one of the biggest pains when working with XAML is getting the Styling just right. We do have more tools now at our disposal like the XAML Previewer in Visual Studio and Visual Studio Mac, but it lacks the touch and feel component of styling. This is where LiveXAML is making a huge difference in developing Xamarin Forms applications. LiveXAML not to be confused with Xamarin's Live Player, allows you to get the updates directly in your actual app. LiveXAML is truly one of the most amazing products I've ever worked with for XAML. 

It really is as simple as installing a single NuGet package and running the application in your Simulator or on your Device. Now you can actually see what your changes are doing, without rebuilding, in an app that is fully functional. There are no short cuts, no limitations like we see with the Live Player or the Previewer.

There are a number of challenges that are hard to handle without a data context behind them. One of them is handling a ListView with a DataTemplateSelector. It's certainly one thing to refine a single ViewCell, but when you have multiple cells that each need to be styled there is no substitute for having real working data which can only happen with your app actually running. This is one the many scenarios where using LiveXAML can really shine as you quickly update the styling and see the changes in your app. 

If you haven't had a chance to check it out head over to http://livexaml.com. 

Prism users have long enjoyed some great Template packs available for Visual Studio and Xamarin Studio. Visual Studio for Mac though has been a real challenge due to problems with the Mono Addins site not building the Prism Addin. It's been a very common request among our Mac users to get this support back.

Since we have been unable to rely on the Mono Addins site, we have decided to simply host our own feed for Prism Users. This new feed will allow you to add and update the Prism Template Pack in Visual Studio for Mac.

So how do you get the Template Pack? Well for starters you will need to add the Prism feed to your Extensions Repositories. Once you have it added, simply refresh the Gallery. You can either use the search bar or expand IDE extensions to find the Prism Template Pack.

Keep in mind that the new Prism Template Pack for Visual Studio for Mac now includes a DryIoc Project template in addition to the Unity Template. Both project templates will create project with the latest stable versions of Prism and Xamarin Forms.

History

It's certainly been no secret that I've told user's that Autofac wasn't really a good choice for Prism Forms. To be honest just looking at the benchmarks between Autofac and DryIoc or SimpleInjector which may soon be supported, Autofac just isn't that appealing to me. The truth though, is that I wasn't just steering people away from Prism Autofac for this reason alone.

Before Prism introduced .NET Standard support, we were limited to targeting Autofac 3.5. As anyone familiar with Autofac is likely aware, the ContainerBuilder.Update(Container) method was deprecated. Autofac quite annoyingly wants to be an immutable container. This is problematic for frameworks like Prism, or any developer who wants to dynamically load dependencies (more on this later). Also part of the problem was that Autofac is a bit unique in the way that it handles registering and resolving. Most containers are responsible for registering dependencies, telling you if something is registered, and resolving that dependency, but Autofac wants to be different with a ContainerBuilder that is used for registering, a central IContainer that knows nothing about itself, but is happy to resolve IComponentContext if you need to inject something into a class to resolve dependencies in a factory method like the one used by the NavigationService to resolve your Views... 

Major Breaking Changes

Prism Forms is architected for a Container that knows how to do stuff, continuing to have the Autofac PrismApplication derive from PrismApplicationBase<IContainer> was a poor choice. To help fix the way Autofac works with Prism Forms this was updated to PrismApplicationBase<ContainerBuilder>. That alone though would provide for a poor experience so this was updated to ensure that the Container property is still the IContainer that is set when the builder is built, and a Builder property was added to give you direct access to the ContainerBuilder being used in PrismApplication to register all of the Prism services. Unlike the builder previously used by PrismApplication, this builder waits to call Builder.Build() until after it registers the base Prism services, anything in your RegisterTypes() and anything in your IPlatformInitializer.

To make this work though, we also had to break all of your View Registrations. The extension methods that we typically include in Prism Forms are based on the Container for registrations. But this never made sense for Autofac, leading to extension methods that would create a builder, and then update the Container. To better align with the intent of how Autofac is meant to work the methods were updated to be based on the ContainerBuilder.

public class App : PrismApplication
{
    protected override void RegisterTypes()
    {
        Builder.RegisterType<Foo>().As<IFoo>();
        Builder.RegisterTypeForNavigation<ViewA>();
    }
}

public class iOSInitializer : IPlatformInitializer
{
    public void RegisterTypes(ContainerBuilder builder)
    {
         builder.RegisterType<SpeakImp>().As<ISpeak>();
    }
}

Modularity

Modularity hasn't been huge in the Prism Forms community like it is in the WPF community. For developers who are familiar with it, Modules are often a major part of their app development. Unfortunately Autofac's desire to be immutable poses some major problems for Modularity with Prism. Prism relies on container mutability for Modules. Part of this is that we must resolve the ModuleCatalog before we run it and initialize any of the Modules. The other part is that Prism allows us to load Modules on demand. This could for instance allow us to ship an application like Lyft and only load the Driver Module if the user is a Driver. Since Autofac is immutable this creates a major problem for us, and OnDemand Modules are out of the question due to the limitations imposed on us by the container. As such the recommended guidance for Autofac users will be to architect modules as follows:

public class AwesomeModule : IModule
{
    public void Initialize() { }

    public static void Initialize(ContainerBuilder builder)
    {
        builder.RegisterType<FooService>().As<IFooService>();
        builder.RegisterTypeForNavigation<ViewA>();
    }
}

public class App : PrismApplication
{
    protected override void RegisterTypes()
    {
        // Initialization must be done before the Container is built.
        AwesomeModule.Initialize(Builder);
    }

    protected override void ConfigureModuleCatalog()
    {
        // Not actually needed for Autofac since all registrations must be done
        // before we build the container.
    }
}

Getting Started

These changes are all available starting with Prism 7.0.0.30-ci in the Prism MyGet feed. If you have not already done so, you can add that feed in either Visual Studio or Visual Studio for Mac and update your existing Prism Application's to the latest CI build. 

If you are starting with a new Project you will want to check out the updated QuickStart Templates which now includes the only Module project template, and full support for the updated Autofac implementation.

Prism 7.0 Sneak Peek

If you're a Xamarin developer, chances are you've been through a struggle or two with NetStandard. NetStandard offers a lot of advantages, but support has been slow going in many cases. Xamarin Forms only recently began shipping NetStandard. Prism users have been asking for a while now to have NetStandard support. Obviously for WPF users NetStandard really doesn't offer any advantages, and for UWP it just creates a few headaches, but that hasn't stopped requests for the Core to support NetStandard or for Prism Forms to be converted. For a while now I've been either pointing people to my preview templates or telling them to use the PackageTargetFallback attribute with the new csproj format. Well, I'm happy to say that Prism for Xamarin Forms is now available in NetStandard!

While NetStandard support is fantastic, I probably wouldn't take the time to write a post just about that. One of the problems we all face is when we run into an issue with a library in our code base, and the issue is fixed on GitHub. The problem is that it may be days, weeks, even months before it is available. So suddenly you have to uninstall the NuGet packages, add the open source library as a git submodule. As Prism moves into the 7.0 update, I'm also very happy to announce the official Prism MyGet feed that is tied into the builds so when new features are added you can immediately expect a new CI package available on MyGet so you can immediately start using the features you need without having to wait for an official release. 

https://www.myget.org/F/prism/api/v3/index.json

Whats New Since 6.3

You may be thinking that NetStandard is great and all but that isn't really new. As part of Prism updating to Xamarin Forms 2.3.5, you will now have full support for working with Prism on macOS applications. 

Another change you can look for starting now in the 7.0 addresses the overhauled OnPlatform starting in Xamarin Forms 2.3.4. Unfortunately the new Xamarin API for OnPlatform uses magic strings, and is cumbersome to say the least if you're working with it from C# code and not in XAML. Prism has updated the IDeviceService and provided a new RuntimePlatform enum. We have also updated Platform dependent View Registrations to use this new RuntimePlatform enum. This will ultimately be a lot cleaner than the previous type based registrations.

Container.RegisterTypeForNavigationOnPlatform<MainPage, MainPageViewModel>("Main",
     new Platform<MainPage_Android>(RuntimePlatform.Android),
     new Platform<MainPage_iOS>(RuntimePlatform.iOS));

Following the deprecation of the previous OnPlatform functions within the Xamarin Forms Device class, we have updated IDevice to deprecate this feature as well and added access both the Xamarin Forms Platform string and our RuntimePlatform enum.

I have been a huge advocate for directly binding to your model's properties. It really saves a lot of headaches with validation and ensuring that changes made on the view update your model to be persisted to your data store. That said even with Prism's DelegateCommand.ObservesProperty, this has been a shortcoming. Thanks to a community contribution this will now be possible in Prism 7.0

ObservesProperty(() => Property.NestedProperty.NestedPoperty)

Another major improvement addresses exceptions thrown during navigation. Prism Forms will now properly log and re-throw exceptions that are thrown when you're navigating. This has been a major pain point in the past where the exceptions were effectively swallowed by the NavigationService and you had no idea what threw an exception or even what the exception was. Many times you might have simply found yourself getting an exception thrown because your MainPage was null and the platform excepted something. 

There have also been a number of reported Navigation Bugs fixed in Prism 7.

Prism for UWP Developers

If you're developing UWP applications with Prism there are a couple of gotcha's that you'll need to know about. 

Starting in Prism 7.0 we've decided to split all of the Platforms/Containers into separate packages. We've done this so that we can rev the platforms separately from one another, and if we update an issue with Prism.Autofac.Wpf, Prism.Autofac.Windows user's won't see a package update and think that something changed. This only affects UWP developers who are using Prism for UWP. You simply need to uninstall the Prism.{Container} package and install the Prism.{Container}.Windows package. (note that this update is not yet available but will be soon)

Whether you're using Prism for UWP or Prism for Xamarin Forms, note that there is a bug with the .NET SDK that will affect you if Prism 7 is the first NetStandard package that you are using. It is easily overcome by adding the file Directory.Build.props next to your solution file, with the following contents:

<?xml version="1.0" encoding="utf-8"?>
<Project>
  <!-- Workaround for https://github.com/dotnet/sdk/pull/908 -->
  <Target Name="GetPackagingOutputs" />
</Project>

Note that if you are developing a UWP application with the Prism QuickStart Template for Xamarin Forms, this has already been added for you.

Whats Coming

As amazing as NetStandard is to finally have behind us, I'm still even more excited by what's coming in 7.0. I wouldn't call this an exhaustive list, but here are some highlights of some features to keep an eye out for in Prism 7:

• Querystring navigation is one of the most amazing things about the Prism Navigation Service, and it's about time that you should be able to dynamically create tabs or use modal navigation through the querystring.
• Removal of support for the Xamarin Forms DependencyService. This really leads to some bad practices, and with IPlatformInitializer there is simply no need to rely on the Dependency Service for Platform specific types.
• An ability to use MVVM and the ViewModelLocator with custom Views as well as Xamarin Forms Pages.

Quickstart Templates for Prism Forms

So you had this great idea for an app... maybe you spent weeks planning with your team or with your client. The day finally comes to create the project. Suddenly you realize that we have this new .NET Standard thing and you want to take advantage of that too. You remember you need icons, you want a Splash Screen... all of the things that go into making an App. For anyone who has done this, you know there's a lot of heavy lifting to be done. In all honesty you could easily spend several days just getting a new project from File -> New to something that you're ready to start working on.

It was for this and so many other reasons that I realized we need better templates, and we need something that can help us whether we're on a Mac or on PC.

There are some very basic things left out of the base Xamarin & Prism Templates. For some developers these just require time that could be better spent on something else, and for other developers it leads them down a path of poor design.

Features

Why should you use these templates? Well here are a couple bullet points:

• Gets you off the ground following Best Practices
• *Starts you off using Prism for Xamarin Forms with either DryIoc or Unity for Dependency Injection
• Already has all of your App Icons added so all you need to do is drop in the replacement files from File Explorer or Finder. There is also a link in there so you can see how to get all of your icons generated for you correctly in all of the sizes with all of the correct naming.
• Starts you off with some base colors to use for your project with information of how to develop a Material Design pallet for your application.
• By default it already has everything you need for Localizing strings in XAML
• It's cross platform, using dotnet new you get the same experience from the command line whether on Mac or PC.
• Item templates to generate Views and ViewModels with support for the common Xamarin Forms pages as well as PopupPages
• Makes it easier to inject variables at Build to protect sensitive project secrets.
• Quickstart with a fully working Todo app working with in memory data, Realm, or Azure Mobile Client
• Included config for MFractor

*NOTE: Autofac & Ninject will be reintroduced once Prism 7 has a public preview.

Best Practices

App development can be simultaneously fun and frustrating. So many developers love Xamarin Forms because it really narrows down the number of API's you need to work with. What it doesn't do is eliminate your need to understand the platform your application will run on. These templates will not eliminate that need either, however they do set you down the right path, with some basic things like a splash screen so your user will at least see something while your app loads. Also included by default is the MVVM Helpers library from James Montemagno so that you can use his ObservableRangeCollection<T> to reduce the notifications sent to the UI when updating or replacing multiple items in your collection. If you don't use it MVVM Helpers you still get a ViewModelBase that will incorporate these properties as well as well as IDeviceService and virtual implementations of INavigationAware, IActiveAware, and IApplicationLifecycle.

Prism

Continuing really with Best Practices, these templates use Prism for Xamarin Forms. Currently the templates support DryIoc and Unity for Dependency Injection. Autofac and Ninject will be added back in once there is a publicly available release of Prism 7.

TabbedPages

Working with TabbedPages has traditionally been one of the more challenging areas of working with Prism. With the QuickStart template this challenge disappears. The template includes two base implementations for a TabbedPage, the PrismTabbedPage and the DynamicTabbedPage. If your TabbedPage inherits from PrismTabbedPage, it will automatically pick up and pass on the NavigationParameters to the Child Pages allowing you to properly initialize them. If you use the DynamicTabbedPage you only need to reference it in your Navigation URI and pass in variables like:

NavigationService.NavigateAsync("TabbedPage?tab=ViewA&tab=ViewB&tab=ViewC");

But it actually gets a little better than that because not only does it pick up tabs but you can also do some deep linking like:

NavigationService.NavigateAsync("TabbedPage?tab=NavigationPage/ViewA/ViewD&tab=NavigationPage/ViewB&tab=ViewC");

This means you can actually support scenarios where your actual tabs contain their own NavigationStack independent of the rest of the application.

App Icons

Applications need a lot of icons and really the templates out there don't do a very good job with App Icons. Most templates out there just leave your deployed app with a broken icon image and require some time getting the icons setup. These templates start you off with icons for your Android and iOS projects. But more than that is the GettingStarted document included in the template gives you the information you need to be able to quickly and efficiently generate a full icon set that you can drop in to replace the default icons with your own icons. Following along with Best Practices, you'll find that the iOS project is using the newer appiconset approach with the app icons as ImageAssets rather than having them in the Resources folder as BundleResources. Similarly on Android you'll find the app icon's are all in the mipmap folders rather than drawable.

Material Design

While my purpose is not to teach Material Design, there are some basics that we can easily include in the template to get you started down the right path. That includes a basic color pallet with information of how to choose new colors. There is also already a Style defined for you to customize the look and feel of a NavigationPage using those colors.

Localization

One of the things I hear over and over, developers in the United States forget some people don't speak English. For most US based dev's Localization is a complete and total afterthought. Interestingly nobody seems to have thought previously that maybe we should provide a template that assumes you want your application easily consumable by people in another country who speak another language. The quickstart template comes complete with all of the helper classes you need to get Localization working in the application and gets the Localization implemented with the DI container using Prism's IPlatformInitializer. There is also a XAML extension provided so all you need to do is include the namespace in your XAML file and use it as needed. The app of course also includes a single Resx file to get you started. You simply need to add the string resources you want to use in your application.

Cross Platform

It might seem weird when we're talking about Xamarin, but seriously it gets frustrating when we're working with a Cross Platform technology and then the developer experience is completely and totally different depending on which platform you are on. One of the most common issues we can see from a templating standpoint is that if I click File -> New, it shouldn't matter whether I'm on Mac or PC, I should be able to decide if I want my project to include iOS, Android, UWP. That's not to say I don't understand that some time may be needed before you can build a UWP app on Mac, but you should at least be able to have the platform as an option so you can work on the codebase from either platform.

Item Templates

Also included are some Item Templates custom built for the included project templates. There are two basic types of Item Templates, Pages and Services. Note that there is currently no way for the dotnet templating engine to pick up what your base namespace is, so you do have to specify this from the command line.

Pages

By default when you call dotnet new prismitem you will get a page. It's assumed that you're using the ViewModelBase from the included Project templates. You can add flags to specify whether you want to implement INavigatingAware, INavigatedAware, INavigationAware, IActiveAware, or IDestructible. By default it implements INavigationAware. There is also a flag to indicate if the page is a Tabbed Child which will automatically implement IActiveAware and INavigatingAware. Currently supported page types include ContentPage, MasterDetailPage, TabbedPage (which inherits from the Quickstart PrismTabbedPage), and PopupPages.

Samples

dotnet new prismitem -namespace MyAwesomeApp -n LoginPage
dotnet new prismitem -namespace MyAwesomeApp -page PopupPage -n SomePage
dotnet new prismitem -namespace MyAwesomeApp -n CustomerDetailPage -child

Services

Chances are your app is probably using some sort of service and if you like testability like I do, then you'll really appreciate that you can create a service with Mock class that will automatically be picked up by the Quickstart template simply by building with the Mock configuration. 

Samples

dotnet new prismitem -item Service -namespace MyAwesomeApp -n LoginService
dotnet new prismitem -item Service -namespace MyAwesomeApp -n LoginService -mocks false

Secrets

All apps have secrets and other variables that we just don't want checked into source control. To better assist with this, the template includes some helpers that will regenerate the Secrets.cs with sensitive variables you want in your codebase. Both the Secrets.cs and secrets.json files have also been added to the included .gitignore, so you can finally develop apps without having to tackle the issue of keeping app secrets out of SCM.

secrets.json

{
  "AuthClientId": "{Your App Client Id}",
  "AppServiceEndpoint": "https://appservicename.azurewebsites.net/"
}

Secrets.cs

namespace YourProject.Helpers
{
    internal static class Secrets
    {
        internal const string AuthClientId = "{Your App Client Id}";

        internal const string AppServiceEndpoint = "https://appservicename.azurewebsites.net/";
    }
}

PropertyChanged.Fody

Part of the MVVM pattern is working with INotifyPropertyChanged. Unfortunately the code can get a bit tedious. 

public class ViewAViewModel : BindableBase
{
    private string _title;
    public string Title
    {
        get => _title;
        set => SetProperty(ref _title, value);
    }

    private MyModel _selectedItem;
    public MyModel SelectedItem
    {
        get => _selectedItem;
        set => SetProperty(ref _selectedItem, value, onChanged: OnSelectedItemChanged);
    }

    private void OnSelectedItemChanged()
    {
        // Do Stuff
    }
}

With PropertyChanged.Fody already included our ViewModels and other Observable objects simply become:

public class ViewAViewModel : BindableBase
{
    public string Title { get; set; }

    public MyModel SelectedItem { get; set; }

    private void OnSelectedItemChanged()
    {
        // Do Stuff
    }
}

Mobile Center

Also bundled into this template is support for the Azure Mobile Center. While this is an opt in feature you can pass in your App Secret for iOS and/or Android from the command line with everything already wired up to send your analytics and crash data to the Azure Mobile Center. This includes an implementation of ILoggerFacade that will create a Mobile Center Analytics Event.

Data Providers

Apps today are so often really connected apps. The Quickstart Template provides you a fully functional TodoApp with the option to use either the Azure Mobile Apps Client with AzureMobileClient.Helpers or to use Realm. Either data provider will start you out with the ability to quickly develop your app with full online/offline sync with the bare minimum of configuration. 

Azure Mobile Client

In addition to simply using the Azure Mobile Client you can additionally decide if you want to use anonymous authentication or if you will require some sort of authentication. If you choose an authentication provider, the Quickstart will provide you base classes for everything you need to get started. This includes scaffolding for custom authentication sources and a fully working implementation for Azure Active Directory B2C with support coming for AAD, Google, Facebook and Microsoft Accounts.

Plugins

Because the full working app uses a PopupPage for the TodoItem detail page, the Quickstart includes Prism.Plugin.Popups, and also optionally includes a Barcode Scanning Service utilizing ZXing.Net.Mobile and is fully registered and configured.

Getting Started

To get started with the templates it's recommended that you install version 2.0 pre3 of the dotnet cli as this contains several fixes in the templating engine. Once that is installed you can install the templates by using the following commands in your cli.

dotnet new -i "Prism.Forms.QuickstartTemplates::*"

You should see the prismitems and prismformsempty templates. The Quickstart template is grouped with the empty template, though you may not see it listed it is still there.

# See the Help and options for the Quickstart Template
dotnet new prismforms -h

#Create your first quickstart
mkdir Contoso.AwesomeApp
cd Contoso.AwesomeApp
dotnet new prismforms -id com.contoso.awesomeapp -fr netstandard1.6 -mc -ios-secret 
     "{your ios secret}" -android-secret "{your android secret}" -data AzureMobileClient 
     -auth AADB2C -client-id "{your AADB2C application id}"
#Be sure the B2CName in secrets.json matches your AAD B2C name