docs: Add an article to enable faster single-targetframework builds i…

…n VS 2022

doc/articles/guides/solution-building-single-targetframework.md

@@ -0,0 +1,83 @@
+---
+uid: Build.Solution.TargetFramework-override
+---
+# Adjust an Uno Solution for a faster build with Visual Studio 2022
+
+The Uno Platform template provides a cross-targeted Class library which includes multiple target frameworks. While building with the command line `dotnet build -f net7.0-ios` does only build the application's head and the class library for `net7.0-ios`, Visual Studio builds all the target frameworks, [regardless of the project head's target framework](https://developercommunity.visualstudio.com/t/Building-a-cross-targeted-project-with-m/651372).
+
+Considering that during development, it is common to work on a single platform at a given time, here's a suggested set of modification that can be performed on the solution to restrict the active build platform:
+
+1. Let's create a set of solution filters to ensure that individual project heads can be loaded:
+
+    1. Create a new app template with **iOS**, **Android**, **WebAssembly** and **Windows** targets   selected.
+    1. Right click on the **.Mobile** and **.Wasm** projects and select **Unload Project**
+    1. On the top level Solution node, right click to select **Save As Solution Filter**, name the    filter **MyApp-Windows-Only.slnf**
+
+    1. Right click on the **Mobile** project, select **Reload Project**
+    1. Unload the **.Windows** project, then save a new solution filter called **MyApp-Mobile-    Only.slnf**
+    1. Repeat the operation with the **.Wasm** project, with a solution filter called **MyApp-Wasm-Only.slnf**
+
+    These solution filters will prevent Visual Studio to restore NuGet packages for TargetFrameworks that will be ignored by the configuration done below.
+
+1. Now next to the solution file, create a file named `targetframework-override.props`:
+
+    ```xml
+    <Project>
+        <Import Project="solution-config.props" Condition="exists('solution-config.props')" />
+
+        <!-- Override the TargetFrameworks list with the one specified in MyAppTargetFrameworkOverride -->
+        <PropertyGroup Condition="'$(MyAppTargetFrameworkOverride)'!=''">
+            <TargetFrameworks>$(MyAppTargetFrameworkOverride)</TargetFrameworks>
+        </PropertyGroup>
+    </Project>
+   ```
+1. Also next to the solution file, create a file named `solution-config.props.sample`:
+
+    ```xml
+    <Project>
+        <PropertyGroup>
+            <!--
+            Uncomment the following line to enable single target framework builds
+            in order to get faster performance when debugging for a single platform.
+
+            Once this file is modified, use the appropriate solution filter to avoid
+            NuGet restore issues.
+
+            Available target frameworks can be found in the project heads of your solution.
+            -->
+            <!-- <MyAppTargetFrameworkOverride>net7.0-ios</MyAppTargetFrameworkOverride> -->
+        </PropertyGroup>
+    </Project>
+    ```
+1. Next, in all projects of the solution which are cross-targeted (with multiple TargetFrameworks values), add the following lines right after the `PropertyGroup` which defines `<TargetFrameworks>`:
+
+    ```xml
+    <!-- Import the TargetFramework override configuration -->
+    <Import Project="../../targetframework-override.props" />
+    ```
+    The file should then look like this:
+    ```xml
+    <Project Sdk="Microsoft.NET.Sdk">
+        <PropertyGroup>
+            <TargetFrameworks>net7.0-windows10.0.18362;net7.0;net7.0-ios;net7.0-android</TargetFrameworks>
+        </PropertyGroup>
+    </Project>
+    <!-- Import the TargetFramework override configuration -->
+    <Import Project="../../targetframework-override.props" />
+    ```
+    > [!NOTE]
+    > If the template is created with `dotnet new`, the path will instead be `../targetframework-override.props`
+1. Create a copy of the file `solution-config.props.sample` next to itself, and name it `solution-config.props`
+1. If using git, add this specific file to the `.gitignore` so it never gets committed. This way, each developer can keep their own version of the file without corrupting the repository.
+1. Commit your changes to the repository.
+
+At this point, your solution is ready for single-TargetFramework use.
+
+For example, to work on `net7.0-ios`:
+1. Before opening the solution, open the `solution-config.props` file and uncomment `MyAppTargetFrameworkOverride` to contain `net7.0-ios`
+1. Open the `MyApp-Mobile-Only.slnf` solution filter in Visual Studio 2022
+1. You should only see the **.Mobile** and **Class Library** projects in your solution
+1. When building and debugging the app, you'll only now build for the target specified in `solution-config.props`.
+
+> [!IMPORTANT]
+> When changing the `MyAppTargetFrameworkOverride` value, make sure to close the solution and reload it so the build system recognizes properly the change.

doc/articles/toc.yml

@@ -394,6 +394,8 @@
                   href: wpf-migration.md
             - name: Creating a cross-targeted library
               href: cross-targeted-libraries.md
+            - name: Faster Single Target App Builds
+              href: solution-building-single-targetframework.md
             - name: Hosting a WebAssembly app
               href: how-to-host-a-webassembly-app.md
             - name: Updating to WinUI 3.0

doc/articles/uno-app-solution-structure.md

@@ -19,3 +19,5 @@ Dependencies in Uno solutions can be added preferably in the app's **Class Libra
 ## Further information
 
 See additional guides on handling platform-specific [C# code](platform-specific-csharp.md) and [XAML markup](platform-specific-xaml.md) in an Uno Platform project.
+
+The Uno Platform solution also [can be further optimized](xref:Build.Solution.TargetFramework-override) to build larger projects with Visual Studio 2022.