microsoft · Scottj1s · Mar 12, 2026 · Mar 12, 2026 · Mar 12, 2026 · Mar 12, 2026
diff --git a/BuildAll.ps1 b/BuildAll.ps1
diff --git a/WindowsAppRuntime.sln b/WindowsAppRuntime.sln
@@ -52,7 +52,7 @@ Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "DynamicDependency_Test_Win3
 		{F76B776E-86F5-48C5-8FC7-D2795ECC9746} = {F76B776E-86F5-48C5-8FC7-D2795ECC9746}
 	EndProjectSection
 EndProject
-Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "WindowsAppRuntime_BootstrapDLL", "dev\WindowsAppRuntime_BootstrapDLL\WindowsAppRuntime_BootstrapDLL.vcxproj", "{F76B776E-86F5-48C5-8FC7-D2795ECC9746}"
+Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "WindowsAppRuntime_BootstrapDLL", "base\dev\WindowsAppRuntime_BootstrapDLL\WindowsAppRuntime_BootstrapDLL.vcxproj", "{F76B776E-86F5-48C5-8FC7-D2795ECC9746}"
 	ProjectSection(ProjectDependencies) = postProject
 		{B73AD907-6164-4294-88FB-F3C9C10DA1F1} = {B73AD907-6164-4294-88FB-F3C9C10DA1F1}
 	EndProjectSection
@@ -233,7 +233,7 @@ Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Bootstrap", "Bootstrap", "{
 EndProject
 Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "CS", "CS", "{536FA8DA-51E2-40A3-8A97-A90FFA75AA18}"
 EndProject
-Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Microsoft.WindowsAppRuntime.Bootstrap.Net", "dev\Bootstrap\CS\Microsoft.WindowsAppRuntime.Bootstrap.Net\Microsoft.WindowsAppRuntime.Bootstrap.Net.csproj", "{D6574FD6-8D13-4412-9FCB-308D44063CDA}"
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Microsoft.WindowsAppRuntime.Bootstrap.Net", "base\dev\Bootstrap\CS\Microsoft.WindowsAppRuntime.Bootstrap.Net\Microsoft.WindowsAppRuntime.Bootstrap.Net.csproj", "{D6574FD6-8D13-4412-9FCB-308D44063CDA}"
 EndProject
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Microsoft.Windows.System.Power.Projection", "dev\Projections\CS\Microsoft.Windows.System.Power\Microsoft.Windows.System.Power.Projection.csproj", "{63ACBA4F-385A-4D04-98AD-263FED501A19}"
 	ProjectSection(ProjectDependencies) = postProject

diff --git a/base/build/AzurePipelinesTemplates/WindowsAppSDK-BuildWindowsAppSDKBase-Stages.yml b/base/build/AzurePipelinesTemplates/WindowsAppSDK-BuildWindowsAppSDKBase-Stages.yml
diff --git a/base/build/NuSpecs/Microsoft.WindowsAppSDK.Arm64Ec.targets b/base/build/NuSpecs/Microsoft.WindowsAppSDK.Arm64Ec.targets
@@ -0,0 +1,32 @@
+<!--
+  Copyright (c) Microsoft Corporation. Licensed under the MIT License
+-->
+<Project xmlns="http://schemas.microsoft.com/developer/msbuild/2003" InitialTargets="ValidateArm64EcConfiguration;WebView2Arm64EcWorkaround">
+
+    <Target Name="ValidateArm64EcConfiguration" Condition="'$(ValidateArm64EcConfiguration)'!='false' and ('$(OutputType)'=='Exe' or '$(OutputType)'=='WinExe' or '$(OutputType)'=='Package')">
+        <Error Condition="'$(WindowsAppSdkSelfContained)'!='true' or '$(WindowsPackageType)'!='None'" 
+            Text="Windows App SDK Arm64EC support currently requires WindowsAppSdkSelfContained=true and WindowsPackageType=None" />
+    </Target>
+
+    <!-- TEMPORARY: Work around WebView2 not supporting arm64ec, when WinAppSDK targets is imported before WebView2 targets -->
+    <ItemDefinitionGroup Condition="'$(EffectivePlatform)'=='arm64ec'">
+        <Link>
+            <AdditionalLibraryDirectories>$(WV2WinRTPath)..\..\build\native\x64;%(AdditionalLibraryDirectories)</AdditionalLibraryDirectories>
+        </Link>
+    </ItemDefinitionGroup>
+    <Target Name="WebView2Arm64EcWorkaround" Condition="'$(EffectivePlatform)'=='arm64ec'">
+        <PropertyGroup>
+            <WebView2BuildRoot>$([MSBuild]::NormalizePath($(WV2WinRTPath), "..\..\build\"))</WebView2BuildRoot>
+        </PropertyGroup>
+        <ItemGroup>
+            <ReferenceCopyLocalPaths Remove="$(WebView2BuildRoot)..\runtimes\win-arm64ec\native_uap\Microsoft.Web.WebView2.Core.dll"/>
+            <ReferenceCopyLocalPaths Include="$(WebView2BuildRoot)..\runtimes\win-x64\native_uap\Microsoft.Web.WebView2.Core.dll"/>
+        </ItemGroup>
+    </Target>
+
+    <!-- TEMPORARY: Work around WebView2 not supporting arm64ec, when WinAppSDK targets is imported after WebView2 targets -->
+    <PropertyGroup>
+        <EffectivePlatform>x64</EffectivePlatform>
+    </PropertyGroup>
+
+</Project>
diff --git a/....WindowsAppSDK.AutoInitializer.CS.targets → ....WindowsAppSDK.AutoInitializer.CS.targets b/....WindowsAppSDK.AutoInitializer.CS.targets → ....WindowsAppSDK.AutoInitializer.CS.targets
diff --git a/...ndowsAppSDK.AutoInitializerCommon.targets → ...ndowsAppSDK.AutoInitializerCommon.targets b/...ndowsAppSDK.AutoInitializerCommon.targets → ...ndowsAppSDK.AutoInitializerCommon.targets
diff --git a/base/build/NuSpecs/Microsoft.WindowsAppSDK.Base.Native.props b/base/build/NuSpecs/Microsoft.WindowsAppSDK.Base.Native.props
@@ -0,0 +1,6 @@
+<!--
+  Copyright (c) Microsoft Corporation. Licensed under the MIT License
+-->
+<Project xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <Import Project="$(MSBuildThisFileDirectory)..\Microsoft.WindowsAppSDK.Base.props" />
+</Project>
diff --git a/base/build/NuSpecs/Microsoft.WindowsAppSDK.Base.TransportPackage.nuspec b/base/build/NuSpecs/Microsoft.WindowsAppSDK.Base.TransportPackage.nuspec
@@ -0,0 +1,15 @@
+<?xml version="1.0" encoding="utf-8"?>
+<package xmlns="http://schemas.microsoft.com/packaging/2010/07/nuspec.xsd">
+     <metadata minClientVersion="3.3">
+         <id>Microsoft.WindowsAppSDK.Base.TransportPackage</id>
+         <version>1.0</version>
+         <title>$id$</title>
+         <authors>Microsoft</authors>
+         <description>Windows App SDK - Base Transport Package</description>
+         <license type="file">license.txt</license>
+         <requireLicenseAcceptance>true</requireLicenseAcceptance>
+         <projectUrl>https://aka.ms/windowsappsdk</projectUrl>
+         <copyright>© Microsoft Corporation. All rights reserved.</copyright>
+         <tags>Microsoft Native Windows WindowsAppSDK</tags>
+     </metadata>
+</package>
diff --git a/base/build/NuSpecs/Microsoft.WindowsAppSDK.Base.TransportPackage.props b/base/build/NuSpecs/Microsoft.WindowsAppSDK.Base.TransportPackage.props
@@ -0,0 +1,10 @@
+<!-- Copyright (c) Microsoft Corporation. All rights reserved. Licensed under the MIT License. See LICENSE in the project root for license information. -->
+<Project DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+
+  <PropertyGroup>
+    <WindowsAppSDKAggregatePackage>true</WindowsAppSDKAggregatePackage>
+  </PropertyGroup>
+
+  <Import Project="$(MSBuildThisFileDirectory)Microsoft.WindowsAppSDK.Base.props" />
+
+</Project>
diff --git a/base/build/NuSpecs/Microsoft.WindowsAppSDK.Base.TransportPackage.targets b/base/build/NuSpecs/Microsoft.WindowsAppSDK.Base.TransportPackage.targets
@@ -0,0 +1,7 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- Copyright (c) Microsoft Corporation. All rights reserved. Licensed under the MIT License. See LICENSE in the project root for license information. -->
+<Project xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+
+  <Import Project="$(MSBuildThisFileDirectory)Microsoft.WindowsAppSDK.Base.targets" />
+
+</Project>
diff --git a/base/build/NuSpecs/Microsoft.WindowsAppSDK.Base.nuspec b/base/build/NuSpecs/Microsoft.WindowsAppSDK.Base.nuspec
@@ -0,0 +1,21 @@
+<?xml version="1.0" encoding="utf-8"?>
+<package xmlns="http://schemas.microsoft.com/packaging/2013/05/nuspec.xsd">
+  <metadata>
+    <id>Microsoft.WindowsAppSDK.Base</id>
+    <version>0.0.0.0</version>
+    <title>Microsoft Windows App SDK Base Package</title>
+    <authors>Microsoft</authors>
+    <owners>Microsoft</owners>
+    <requireLicenseAcceptance>true</requireLicenseAcceptance>
+    <license type="file">license.txt</license>
+    <projectUrl>https://github.com/microsoft/windowsappsdk</projectUrl>
+    <iconUrl>https://raw.githubusercontent.com/microsoft/WindowsAppSDK/main/assets/WindowsAppSDK64.png</iconUrl>
+    <description>The Windows App SDK empowers all Windows Desktop apps with modern Windows UI, APIs, and platform features, including back-compat support. This is a package that is used as a dependency by other Windows App SDK component packages and not meant to be directly referenced.</description>
+    <copyright>© Microsoft Corporation. All rights reserved.</copyright>
+    <tags>Windows "Windows App SDK" WinAppSDK WinUI XAML Fluent Controls Downlevel Compatibility TreeView ColorPicker NavigationView MenuBar Resources Native DWriteCore "Interactive Experiences" ixp "Project Reunion" ProjectReunion</tags>
+    <dependencies>
+      <dependency id="Microsoft.Windows.SDK.BuildTools" version="10.0.26100.4654" />
+      <dependency id="Microsoft.Windows.SDK.BuildTools.MSIX" version="0.0.0.0" />
+    </dependencies>
+  </metadata>
+</package>
diff --git a/base/build/NuSpecs/Microsoft.WindowsAppSDK.Base.props b/base/build/NuSpecs/Microsoft.WindowsAppSDK.Base.props
@@ -0,0 +1,23 @@
+<!--
+  Copyright (c) Microsoft Corporation. Licensed under the MIT License
+-->
+<Project xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <PropertyGroup>
+    <PrepareForBuildDependsOn>$(PrepareForBuildDependsOn);WindowsAppSDKVerifyKitVersion</PrepareForBuildDependsOn>
+  </PropertyGroup>
+
+  <Target Name="WindowsAppSDKVerifyKitVersion" Condition="'$(WindowsAppSDKVerifyKitVersion)'!='false' and '@(Midl)'!=''">
+    <PropertyGroup>
+      <WindowsAppSDKAtLeast22000>false</WindowsAppSDKAtLeast22000>
+      <WindowsAppSDKAtLeast22000 Condition="'$(TargetPlatformVersion)' &gt;= '10.0.22000.0'">true</WindowsAppSDKAtLeast22000>
+    </PropertyGroup>
+
+    <ItemGroup>
+      <!-- Checking if any component packages are experimental such as Microsoft.WindowsAppSDK[.Component].<ver>-experimental or Microsoft.WindowsAppSDK[.Component]\<ver>-experimental. -->
+      <!-- The regex doesn't directly check if it is experimental, but rather if it is not a preview or a stable build (with or without -stable suffix) to allow for components to use other suffixes. -->
+      <_ExperimentalPackages Include="@(WindowsAppSdkComponentPackages)" Condition="$([System.Text.RegularExpressions.Regex]::IsMatch('%(Identity)', 'Microsoft\.WindowsAppSDK([.\\][^\\]*)*-(?!stable)(?!preview)'))" />
+    </ItemGroup>
+
+    <Error Condition="$(WindowsAppSDKAtLeast22000) != 'true' and '@(_ExperimentalPackages)' != ''" Text="This version of Windows App SDK requires Windows SDK version 10.0.22000.0 or later." />
+  </Target>
+</Project>
diff --git a/base/build/NuSpecs/Microsoft.WindowsAppSDK.Base.targets b/base/build/NuSpecs/Microsoft.WindowsAppSDK.Base.targets
@@ -0,0 +1,112 @@
+<!--
+  Copyright (c) Microsoft Corporation. Licensed under the MIT License
+-->
+<Project xmlns="http://schemas.microsoft.com/developer/msbuild/2003" InitialTargets="WindowsAppSDKNotifySelfContainedMode;WindowsAppSDKFrameworkPackageDependentWithoutPackages">
+
+    <!-- Compute the effective minimum target platform version for OS-version-dependent behavior.
+         Prefers TargetPlatformMinVersion; falls back to TargetPlatformVersion if not set. -->
+    <PropertyGroup>
+        <_WindowsAppSDKMinTPV Condition="'$(TargetPlatformMinVersion)' != ''">$(TargetPlatformMinVersion)</_WindowsAppSDKMinTPV>
+        <_WindowsAppSDKMinTPV Condition="'$(_WindowsAppSDKMinTPV)' == ''">$(TargetPlatformVersion)</_WindowsAppSDKMinTPV>
+    </PropertyGroup>
+
+    <!-- Import shared targets (SC default, TPVBuild computation, validation targets) -->
+    <Import Project="$(MSBuildThisFileDirectory)Microsoft.WindowsAppSDK.BaseCommon.targets" />
+
+    <Import Project="$(MSBuildThisFileDirectory)Microsoft.WindowsAppSDK.SingleFile.targets" Condition="'$(PublishSingleFile)'=='true'"/>
+    <Import Project="$(MSBuildThisFileDirectory)Microsoft.WindowsAppSDK.SingleProject.targets" Condition="'$(EnableMsixTooling)'=='true'"/>
+
+    <!--Import Arm64EC configuration support -->
+    <Import Project="$(MSBuildThisFileDirectory)Microsoft.WindowsAppSDK.Arm64Ec.targets" Condition="'$(Platform)'=='arm64ec'"/>
+
+    <!--Import after all other props to ensure WindowsAppSDKSelfContained is set (required for SelfContained projects)-->
+    <Import Project="$(MSBuildThisFileDirectory)Microsoft.WindowsAppSDK.SelfContained.targets" Condition="'$(WindowsAppSDKSelfContained)'=='true'"/>
+
+    <!-- Bootstrapper and auto-initialization support -->
+    <Import Project="$(MSBuildThisFileDirectory)Microsoft.WindowsAppSDK.BootstrapCommon.targets" />
+    <Import Project="$(MSBuildThisFileDirectory)Microsoft.WindowsAppSDK.Bootstrap.CS.targets" Condition="'$(WindowsAppSdkBootstrapInitialize)' == 'true'"/>
+
+    <Import Project="$(MSBuildThisFileDirectory)Microsoft.WindowsAppSDK.UndockedRegFreeWinRTCommon.targets" />
+    <Import Project="$(MSBuildThisFileDirectory)Microsoft.WindowsAppSDK.UndockedRegFreeWinRT.CS.targets" Condition="'$(WindowsAppSdkUndockedRegFreeWinRTInitialize)' == 'true'"/>
+
+    <Import Project="$(MSBuildThisFileDirectory)Microsoft.WindowsAppSDK.DeploymentManagerCommon.targets" />
+    <Import Project="$(MSBuildThisFileDirectory)Microsoft.WindowsAppSDK.DeploymentManager.CS.targets" Condition="'$(WindowsAppSdkDeploymentManagerInitialize)' == 'true'"/>
+
+    <Import Project="$(MSBuildThisFileDirectory)Microsoft.WindowsAppSDK.CompatibilitySetter.CS.targets" />
+
+    <Import Project="$(MSBuildThisFileDirectory)Microsoft.WindowsAppSDK.AutoInitializerCommon.targets" />
+    <Import Project="$(MSBuildThisFileDirectory)Microsoft.WindowsAppSDK.AutoInitializer.CS.targets" Condition="'$(WindowsAppSdkAutoInitialize)' == 'true'"/>
+
+    <ItemGroup>
+      <Compile Condition="'$(WindowsAppSDKAggregatePackage)' == 'true' and '$(WindowsAppSdkIncludeVersionInfo)'=='true'" Include="$(MSBuildThisFileDirectory)..\include\WindowsAppSDK-VersionInfo.cs" />
+    </ItemGroup>
+
+    <!-- Remove Bootstrap binaries from output when they are not needed:
+         - SelfContained=true: OS provides dynamic dependency support
+         - BootstrapInitialize explicitly disabled (on Germanium+, where it's optional)
+         - Packaged apps (appxmanifest handles framework dependency) -->
+    <Target Name="WindowsAppSDKRemoveBootstrapFromOutput" BeforeTargets="_CopyFilesMarkedCopyLocal;CopyFilesToOutputDirectory"
+            Condition="'$(WindowsAppSDKSelfContained)'=='true' or ('$(WindowsAppSdkBootstrapInitialize)' == 'false' and '$(_WindowsAppSDKKeepBootstrapBinaries)' != 'true')">
+        <ItemGroup>
+            <ReferenceCopyLocalPaths Remove="@(ReferenceCopyLocalPaths)" Condition="'%(Filename)' == 'Microsoft.WindowsAppRuntime.Bootstrap'" />
+            <ReferenceCopyLocalPaths Remove="@(ReferenceCopyLocalPaths)" Condition="'%(Filename)' == 'Microsoft.WindowsAppRuntime.Bootstrap.Net'" />
+            <RuntimeCopyLocalItems Remove="@(RuntimeCopyLocalItems)" Condition="'%(Filename)' == 'Microsoft.WindowsAppRuntime.Bootstrap'" />
+            <NativeCopyLocalItems Remove="@(NativeCopyLocalItems)" Condition="'%(Filename)' == 'Microsoft.WindowsAppRuntime.Bootstrap'" />
+        </ItemGroup>
+    </Target>
+
+    <Target Name="RemoveVCLibsFrameworkPackageDependencies" BeforeTargets="_ConvertItems" AfterTargets="GetInstalledSDKLocations" Condition="'$(MSBuildProjectExtension)'=='.wapproj'">
+        <ItemGroup>
+            <!-- Remove VCLibs references made by DesktopBridge _ResolveVCLibDependencies -->
+            <FrameworkSdkPackage Remove="@(FrameworkPackageDependencies)"/>
+            <!-- And prevent additional VCLibs references made by DesktopBridge _ConvertItems -->
+            <InstalledSDKLocations Remove="@(InstalledSDKLocations)" />
+        </ItemGroup>
+    </Target>
+
+    <PropertyGroup>
+        <ResolveReferencesDependsOn Condition="'$(MSBuildProjectExtension)'=='.csproj' and '$(WindowsAppSDKVerifyCsWinRtVersions)'!='false' and '$(WindowsAppSDKVerifyWinrtRuntimeVersion)'!='false'">
+            $(ResolveReferencesDependsOn);WindowsAppSDKVerifyCsWinRtVersions
+        </ResolveReferencesDependsOn>
+    </PropertyGroup>
+    <Target Name="WindowsAppSDKVerifyCsWinRtVersions" DependsOnTargets="ResolveAssemblyReferences">
+        <PropertyGroup>
+            <_TargetFrameworkRequired>6.0</_TargetFrameworkRequired>
+            <_TargetFrameworkCompatible Condition="$([MSBuild]::VersionGreaterThanOrEquals($(TargetFrameworkVersion), '$(_TargetFrameworkRequired)'))">True</_TargetFrameworkCompatible>
+        </PropertyGroup>
+        <ItemGroup>
+            <_WindowsSdkPackage Include="$(WindowsSdkPackageVersion)" Condition="'$(WindowsSdkPackageVersion)' != ''">
+                <Referenced>$(WindowsSdkPackageVersion)</Referenced>
+                <Required>10.0.$([System.Version]::Parse("$(WindowsSdkPackageVersion.Split('-')[0])").Build).38</Required>
+            </_WindowsSdkPackage>
+            <_WindowsSdkPackage Include="@(ResolvedFrameworkReference)" Condition="'$(WindowsSdkPackageVersion)' == '' and '@(ResolvedFrameworkReference)' != '' and 
+                    ('%(Identity)' == 'Microsoft.Windows.SDK.NET.Ref' or '%(Identity)' == 'Microsoft.Windows.SDK.NET.Ref.Windows')">
+                <Referenced>%(ResolvedFrameworkReference.TargetingPackVersion)</Referenced>
+                <Required>10.0.$([System.Version]::Parse("%(ResolvedFrameworkReference.TargetingPackVersion)").Build).38</Required>
+            </_WindowsSdkPackage>
+            <_WindowsSdkCompatible Include="@(_WindowsSdkPackage)" Condition="'@(_WindowsSdkPackage)' != '' and $([MSBuild]::VersionGreaterThanOrEquals(%(Referenced), %(Required)))" />
+        </ItemGroup>
+        <PropertyGroup>
+            <_WindowsSdkPackageRequired>@(_WindowsSdkPackage->'%(Required)')</_WindowsSdkPackageRequired>
+        </PropertyGroup>
+        <Error Condition="'$(_TargetFrameworkCompatible)'!='True'"
+            Text="This version of the Windows App SDK requires .NET $(_TargetFrameworkRequired).
+    Please update your TargetFramework to specify net$(_TargetFrameworkRequired) or later.
+" />
+        <Error Condition="'$(_WindowsSdkPackageRequired)'==''"
+            Text="The Windows App SDK requires a specific target OS version. Please set the &lt;TargetFramework&gt; property to an appropriate value. For more information, visit https://aka.ms/winappsdk.TFM." 
+            HelpLink="https://aka.ms/winappsdk.TFM" />
+        <Error Condition="'@(_WindowsSdkCompatible)'==''"
+            Text="This version of the Windows App SDK requires Microsoft.Windows.SDK.NET.Ref $(_WindowsSdkPackageRequired) or later. Please add property &lt;WindowsSdkPackageVersion&gt;$(_WindowsSdkPackageRequired)&lt;/WindowsSdkPackageVersion&gt; to your project. For more information, visit https://aka.ms/winappsdk.winsdkpkg." 
+            HelpLink="https://aka.ms/winappsdk.winsdkpkg" />
+        <Warning Condition="'$(CsWinRTAotOptimizerEnabled)' == '' and '$(PublishAot)'=='true'"
+            Text="This version of the Windows App SDK requires CsWinRTAotOptimizerEnabled set to enable PublishAot support.
+    This will be automatically set if you update to .NET SDK 6.0.134, 6.0.426, 8.0.109, 8.0.305 or 8.0.402 (or later).
+    Or you can add a reference to the Microsoft.Windows.CsWinRT 2.1.1 (or later) NuGet package which will also set it.
+" />
+
+        <Warning Condition="'$(CsWinRTAotOptimizerEnabled)' != '' and '$(CsWinRTAotOptimizerEnabled)' != 'true' and '$(PublishAot)'=='true'"
+            Text="This version of the Windows App SDK requires CsWinRTAotOptimizerEnabled set to true to enable PublishAot support." />
+    </Target>
+
+</Project>