Reverts IsXamarinForms changes in Playground (#2754)

* Reverts MvvmCross\Projects\Directory.build.props IsXamarinForms changes because it was causing the Xamarin.Forms library to be imported into Playground.Droid.

Adds <PackageReference/> to import Xamarin.Forms for Playground.Forms.* projects.

* Moving Xamarin Forms Package Reference into separate targets file - allows for XF version to be changed in one place

Directory.build.props

@@ -35,8 +35,4 @@
   <ItemGroup Condition="'$(IsTestProject)' != 'true' and '$(SourceLinkEnabled)' != 'false' and '$(IsLibraryProject)' == 'true'">
     <PackageReference Include="SourceLink.Create.CommandLine" Version="2.8.0" PrivateAssets="All" /> 
   </ItemGroup>
-
-  <ItemGroup Condition="'$(IsXamarinForms)' == 'true'">
-    <PackageReference Include="Xamarin.Forms" Version="2.5.0.280555" />
-  </ItemGroup>
 </Project>

Directory.build.targets

@@ -38,4 +38,6 @@
   <ItemGroup Condition="$(TargetFramework.StartsWith('uap')) and '$(IsLibraryProject)' == 'true' ">
     <PackageReference Include="Microsoft.NETCore.UniversalWindowsPlatform" Version="6.0.8" />
   </ItemGroup>
+
+  <Import Project="XamarinForms.targets" Condition="'$(IsXamarinForms)' == 'true'"/>
 </Project>

Projects/Directory.build.props

@@ -12,10 +12,5 @@
 
     <Platform>AnyCPU</Platform>
     <DebugType>full</DebugType>
-    <IsXamarinForms>$(MSBuildProjectName.Contains('.Forms'))</IsXamarinForms>
   </PropertyGroup>
-
-  <ItemGroup Condition="'$(IsXamarinForms)' == 'true'">
-    <PackageReference Include="Xamarin.Forms" Version="2.5.0.280555" />
-  </ItemGroup>
 </Project>

Projects/Playground/Playground.Forms.Droid/Playground.Forms.Droid.csproj

@@ -200,5 +200,6 @@
       <Name>Playground.Forms.UI</Name>
     </ProjectReference>
   </ItemGroup>
+  <Import Project="..\..\..\XamarinForms.targets" />
   <Import Project="$(MSBuildExtensionsPath)\Xamarin\Android\Xamarin.Android.CSharp.targets" />
 </Project>

Projects/Playground/Playground.Forms.Mac/Playground.Forms.Mac.csproj

@@ -120,10 +120,6 @@
       <Name>Playground.Forms.UI</Name>
     </ProjectReference>
   </ItemGroup>
-  <ItemGroup>
-    <PackageReference Include="Xamarin.Forms">
-      <Version>2.5.0.280555</Version>
-    </PackageReference>
-  </ItemGroup>
+  <Import Project="..\..\..\XamarinForms.targets" />
   <Import Project="$(MSBuildExtensionsPath)\Xamarin\Mac\Xamarin.Mac.CSharp.targets" />
 </Project>

Projects/Playground/Playground.Forms.UI/Playground.Forms.UI.csproj

@@ -13,4 +13,5 @@
     <ProjectReference Include="..\Playground.Core\Playground.Core.csproj" />
   </ItemGroup>
 
+  <Import Project="..\..\..\XamarinForms.targets" />
 </Project>

Projects/Playground/Playground.Forms.Uwp/Playground.Forms.Uwp.csproj

@@ -176,6 +176,7 @@
       <Name>Playground.Forms.UI</Name>
     </ProjectReference>
   </ItemGroup>
+  <Import Project="..\..\..\XamarinForms.targets" />
   <Import Project="$(MSBuildExtensionsPath)\Microsoft\WindowsXaml\v$(VisualStudioVersion)\Microsoft.Windows.UI.Xaml.CSharp.targets" />
   <!-- To modify your build process, add your task inside one of the targets below and uncomment it. 
        Other similar extension points exist, see Microsoft.Common.targets.

Projects/Playground/Playground.Forms.Wpf/Playground.Forms.Wpf.csproj

@@ -125,5 +125,6 @@
       <LastGenOutput>Resources.Designer.cs</LastGenOutput>
     </EmbeddedResource>
   </ItemGroup>
+  <Import Project="..\..\..\XamarinForms.targets" />
   <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
 </Project>

Projects/Playground/Playground.Forms.iOS/Playground.Forms.iOS.csproj

@@ -156,5 +156,6 @@
     <BundleResource Include="Resources\MvvmCross%402x.png" />
     <BundleResource Include="Resources\MvvmCross%403x.png" />
   </ItemGroup>
+  <Import Project="..\..\..\XamarinForms.targets" />
   <Import Project="$(MSBuildExtensionsPath)\Xamarin\iOS\Xamarin.iOS.CSharp.targets" />
 </Project>

XamarinForms.targets

@@ -0,0 +1,5 @@
+<Project>
+  <ItemGroup>
+    <PackageReference Include="Xamarin.Forms" Version="2.5.0.280555" />
+  </ItemGroup>
+</Project>