Fix "Cancel" button in the C# and C++ wapproj templates so that it returns to the "Configure your new project" menu instead of creating a broken project

dev/Templates/Dotnet/Test-DotnetNewTemplates.ps1

@@ -453,31 +453,95 @@ function Get-LatestOfficialWasdkVersion {
     $sourceFeed = 'https://microsoft.pkgs.visualstudio.com/ProjectReunion/_packaging/Project.Reunion.nuget.internal/nuget/v3/flat2/microsoft.windowsappsdk/index.json'
     $excludedVersionPrefixes = @('2.63.')
     $token = $env:SYSTEM_ACCESSTOKEN
-    if ([string]::IsNullOrWhiteSpace($token)) {
-        Write-Warning "SYSTEM_ACCESSTOKEN is not set; cannot query the package source for versions."
-        return $null
-    }
     try {
-        [Net.ServicePointManager]::SecurityProtocol = [Net.ServicePointManager]::SecurityProtocol -bor [Net.SecurityProtocolType]::Tls12
-        $response = Invoke-RestMethod -Uri $sourceFeed -Headers @{ Authorization = "Bearer $token" } -TimeoutSec 30 -ErrorAction Stop
-        $latest = $null
-        foreach ($v in $response.versions) {
-            if ($v -match '-') { continue }   # skip prerelease
-            $excluded = $false
-            foreach ($p in $excludedVersionPrefixes) { if ($v.StartsWith($p)) { $excluded = $true; break } }
-            if ($excluded) { continue }
-            $parsed = $null
-            if (-not [version]::TryParse($v, [ref]$parsed)) { continue }
-            if (($null -eq $latest) -or ($parsed -gt $latest.Ver)) {
-                $latest = [pscustomobject]@{ Raw = $v; Ver = $parsed }
+        # SYSTEM_ACCESSTOKEN is a pipeline variable. Use nuget CLI when running outside of pipeline runs
+        if ([string]::IsNullOrWhiteSpace($token)) {
+            Write-Warning "SYSTEM_ACCESSTOKEN is not set; cannot query package source for latest official Microsoft.WindowsAppSDK version. Using NuGet CLI instead"
+            $packageId = 'Microsoft.WindowsAppSDK'
+            $sourceFeed = 'https://microsoft.pkgs.visualstudio.com/ProjectReunion/_packaging/Project.Reunion.nuget.internal/nuget/v3/index.json'
+            $json = & dotnet package search $packageId `
+                --source $sourceFeed `
+                --exact-match `
+                --format json `
+                --verbosity quiet
+
+            if ($LASTEXITCODE -ne 0) {
+                throw "dotnet package search failed with exit code $LASTEXITCODE."
             }
-        }
-        if ($latest) {
-            Write-Host "Latest official Microsoft.WindowsAppSDK = $($latest.Raw) (excluded prerelease and $($excludedVersionPrefixes -join ', ')*)"
+
+            $response = $json | ConvertFrom-Json
+
+            $problems = @()
+
+            if ($response.PSObject.Properties['problems']) {
+                $problems += @($response.problems)
+            }
+
+            foreach ($result in @($response.searchResult)) {
+                if ($result.PSObject.Properties['problems']) {
+                    $problems += @($result.problems)
+                }
+            }
+
+            if ($problems.Count -gt 0) {
+                throw ($problems | ForEach-Object { $_.text } | Join-String -Separator "`n")
+            }
+
+            $versions = foreach ($result in @($response.searchResult)) {
+                foreach ($package in @($result.packages)) {
+                    if ($package.id -ine $packageId) {
+                        continue
+                    }
+
+                    if ($package.PSObject.Properties['version']) {
+                        $package.version
+                    }
+                    elseif ($package.PSObject.Properties['latestVersion']) {
+                        $package.latestVersion
+                    }
+                }
+            }
+            $latest = $versions |
+                Where-Object {
+                    $version = $_
+                    -not ($excludedVersionPrefixes | Where-Object {
+                        $version.StartsWith($_)
+                    })
+                } |
+                ForEach-Object {
+                    [pscustomobject]@{
+                        Raw = $_
+                        Ver = [version]$_
+                    }
+                } |
+                Sort-Object Ver -Descending |
+                Select-Object -First 1
+
             return $latest.Raw
         }
-        Write-Warning "No official Microsoft.WindowsAppSDK version found on the package source."
-        return $null
+        else
+        {
+            [Net.ServicePointManager]::SecurityProtocol = [Net.ServicePointManager]::SecurityProtocol -bor [Net.SecurityProtocolType]::Tls12
+            $response = Invoke-RestMethod -Uri $sourceFeed -Headers @{ Authorization = "Bearer $token" } -TimeoutSec 30 -ErrorAction Stop
+            $latest = $null
+            foreach ($v in $response.versions) {
+                if ($v -match '-') { continue }   # skip prerelease
+                $excluded = $false
+                foreach ($p in $excludedVersionPrefixes) { if ($v.StartsWith($p)) { $excluded = $true; break } }
+                if ($excluded) { continue }
+                $parsed = $null
+                if (-not [version]::TryParse($v, [ref]$parsed)) { continue }
+                if (($null -eq $latest) -or ($parsed -gt $latest.Ver)) {
+                    $latest = [pscustomobject]@{ Raw = $v; Ver = $parsed }
+                }
+            }
+            if ($latest) {
+                Write-Host "Latest official Microsoft.WindowsAppSDK = $($latest.Raw) (excluded prerelease and $($excludedVersionPrefixes -join ', ')*)"
+                return $latest.Raw
+            }
+            Write-Warning "No official Microsoft.WindowsAppSDK version found on the package source."
+            return $null
+        }
     }
     catch {
         Write-Warning "Failed to query the package source for versions: $($_.Exception.Message)"

dev/Templates/Source/ProjectTemplates/Desktop/CSharp/PackagedApp/BlankApp/ProjectTemplate.csproj

@@ -21,9 +21,9 @@
   </ItemGroup>
 
   <ItemGroup>
-    <PackageReference Include="Microsoft.Windows.SDK.BuildTools" Version="$WindowsSdkBuildToolsVersion$" />
-    <PackageReference Include="Microsoft.WindowsAppSDK" Version="$WindowsAppSdkVersion$" />
-    <PackageReference Include="Microsoft.Windows.SDK.BuildTools.WinApp" Version="$WindowsSdkBuildToolsWinAppVersion$" />
+    <PackageReference Include="Microsoft.Windows.SDK.BuildTools" Version="$ext_WindowsSdkBuildToolsVersion$" />
+    <PackageReference Include="Microsoft.WindowsAppSDK" Version="$ext_WindowsAppSdkVersion$" />
+    <PackageReference Include="Microsoft.Windows.SDK.BuildTools.WinApp" Version="$ext_WindowsSdkBuildToolsWinAppVersion$" />
   </ItemGroup>
 
     <!-- Publish Properties -->

dev/Templates/Source/ProjectTemplates/Desktop/CSharp/PackagedApp/WapProj/WapProjTemplate.wapproj

@@ -42,11 +42,11 @@
 
   <PropertyGroup>
     <ProjectGuid>$guid1$</ProjectGuid>
-    <TargetPlatformVersion>$targetplatformversion$</TargetPlatformVersion>
-    <TargetPlatformMinVersion>$targetplatformminversion$</TargetPlatformMinVersion>
+    <TargetPlatformVersion>$ext_targetplatformversion$</TargetPlatformVersion>
+    <TargetPlatformMinVersion>$ext_targetplatformminversion$</TargetPlatformMinVersion>
     <AssetTargetFallback>$ext_DotNetVersion$-windows$(TargetPlatformVersion);$(AssetTargetFallback)</AssetTargetFallback>
     <DefaultLanguage>$currentuiculturename$</DefaultLanguage>
-    $if$($includeKeyFile$==true)
+    $if$($ext_includeKeyFile$==true)
     <PackageCertificateKeyFile>$projectname$_TemporaryKey.pfx</PackageCertificateKeyFile>
     $endif$
     <AppxPackageSigningEnabled>false</AppxPackageSigningEnabled>
@@ -56,7 +56,7 @@
     <AppxManifest Include="Package.appxmanifest">
       <SubType>Designer</SubType>
     </AppxManifest>
-    $if$($includeKeyFile$==true)
+    $if$($ext_includeKeyFile$==true)
     <None Include="$projectname$_TemporaryKey.pfx" />
     $endif$
   </ItemGroup>

dev/Templates/Source/ProjectTemplates/Desktop/CSharp/PackagedApp/WapProj/WinUI.Desktop.Cs.WapProj.vstemplate

@@ -40,19 +40,9 @@
       <ProjectItem ReplaceParameters="false" TargetFileName="Images\Wide310x150Logo.scale-200.png">Wide310x150Logo.scale-200.png</ProjectItem>
     </Project>      
   </TemplateContent>
-  <WizardExtension>
-    <Assembly>Microsoft.VisualStudio.Universal.TemplateWizards, Version=16.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a</Assembly>
-    <FullClassName>Microsoft.VisualStudio.Universal.TemplateWizards.PlatformVersion.Wizard</FullClassName>
-  </WizardExtension>
   <WizardExtension>
     <!-- Generates Publisher name for appxmanifest -->
     <Assembly>Microsoft.VisualStudio.WinRT.TemplateWizards, Version=16.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a</Assembly>
     <FullClassName>Microsoft.VisualStudio.WinRT.TemplateWizards.UpdatePublisherInManifestWizard</FullClassName>
   </WizardExtension>
-  <WizardData>
-    <MinSupportedVersion>10.0.17763.0</MinSupportedVersion>
-    <SkipXamlCompilerCheck>true</SkipXamlCompilerCheck>
-    <UseWindowsSdkBuildToolsPackage>true</UseWindowsSdkBuildToolsPackage>
-    <UseSdkFallbackFile>true</UseSdkFallbackFile>
-  </WizardData>
 </VSTemplate>

dev/Templates/Source/ProjectTemplates/Desktop/CSharp/PackagedApp/WinUI.Desktop.Cs.PackagedApp.vstemplate

@@ -26,10 +26,23 @@
   <TemplateContent PreferedSolutionConfiguration="Debug|x64">
     <CustomParameters>
       <CustomParameter Name="$DotNetVersion$" Value="FIXME-Verify-Directory.Build.Targets-XmlPoke-Queries"/>
+      <CustomParameter Name="$WindowsAppSdkVersion$" Value="*" />
+      <CustomParameter Name="$WindowsSdkBuildToolsVersion$" Value="*" />
+      <CustomParameter Name="$WindowsSdkBuildToolsWinAppVersion$" Value="*" />
     </CustomParameters>
     <ProjectCollection>
       <ProjectTemplateLink ProjectName="$projectname$ (Package)" CopyParameters="true">WapProj\WinUI.Desktop.Cs.WapProj.vstemplate</ProjectTemplateLink>
       <ProjectTemplateLink ProjectName="$projectname$" CopyParameters="true">BlankApp\WinUI.Desktop.Cs.BlankApp.vstemplate</ProjectTemplateLink>
     </ProjectCollection>
   </TemplateContent>
+  <WizardExtension>
+    <Assembly>Microsoft.VisualStudio.Universal.TemplateWizards, Version=16.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a</Assembly>
+    <FullClassName>Microsoft.VisualStudio.Universal.TemplateWizards.PlatformVersion.Wizard</FullClassName>
+  </WizardExtension>
+  <WizardData>
+    <MinSupportedVersion>10.0.17763.0</MinSupportedVersion>
+    <SkipXamlCompilerCheck>true</SkipXamlCompilerCheck>
+    <UseWindowsSdkBuildToolsPackage>true</UseWindowsSdkBuildToolsPackage>
+    <UseSdkFallbackFile>true</UseSdkFallbackFile>
+  </WizardData>
 </VSTemplate>

dev/Templates/Source/ProjectTemplates/Desktop/CppWinRT/PackagedApp/WapProj/Package-managed.appxmanifest

@@ -11,7 +11,7 @@
 
   <Identity
     Name="$guid9$"
-    Publisher="$XmlEscapedPublisherDistinguishedName$"
+    Publisher="$ext_XmlEscapedPublisherDistinguishedName$"
     Version="1.0.0.0" />
 
   <mp:PhoneIdentity PhoneProductId="$guid9$" PhonePublisherId="00000000-0000-0000-0000-000000000000"/>

dev/Templates/Source/ProjectTemplates/Desktop/CppWinRT/PackagedApp/WapProj/WapProjTemplate.wapproj

@@ -43,10 +43,10 @@
 
   <PropertyGroup>
     <ProjectGuid>$guid1$</ProjectGuid>
-    <TargetPlatformVersion>$targetplatformversion$</TargetPlatformVersion>
-    <TargetPlatformMinVersion>$targetplatformminversion$</TargetPlatformMinVersion>
+    <TargetPlatformVersion>$ext_targetplatformversion$</TargetPlatformVersion>
+    <TargetPlatformMinVersion>$ext_targetplatformminversion$</TargetPlatformMinVersion>
     <DefaultLanguage>$currentuiculturename$</DefaultLanguage>
-    $if$($includeKeyFile$==true)
+    $if$($ext_includeKeyFile$==true)
     <PackageCertificateKeyFile>$projectname$_TemporaryKey.pfx</PackageCertificateKeyFile>
     $endif$
     <AppxPackageSigningEnabled>false</AppxPackageSigningEnabled>
@@ -56,7 +56,7 @@
     <AppxManifest Include="Package.appxmanifest">
       <SubType>Designer</SubType>
     </AppxManifest>
-    $if$($includeKeyFile$==true)
+    $if$($ext_includeKeyFile$==true)
     <None Include="$projectname$_TemporaryKey.pfx" />
     $endif$
   </ItemGroup>

dev/Templates/Source/ProjectTemplates/Desktop/CppWinRT/PackagedApp/WapProj/WinUI.Desktop.CppWinRT.WapProj.vstemplate

@@ -39,21 +39,8 @@
       <CustomParameter Name="$NuGetPackages$" Value="Microsoft.WindowsAppSDK;Microsoft.Windows.SDK.BuildTools"/>
     </CustomParameters>
   </TemplateContent>
-  <WizardExtension>
-    <Assembly>Microsoft.VisualStudio.Universal.TemplateWizards, Version=16.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a</Assembly>
-    <FullClassName>Microsoft.VisualStudio.Universal.TemplateWizards.PlatformVersion.Wizard</FullClassName>
-  </WizardExtension>
-  <WizardExtension>
-    <!-- Generates Publisher name for appxmanifest -->
-    <Assembly>Microsoft.VisualStudio.WinRT.TemplateWizards, Version=16.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a</Assembly>
-    <FullClassName>Microsoft.VisualStudio.WinRT.TemplateWizards.UpdatePublisherInManifestWizard</FullClassName>
-  </WizardExtension>
   <WizardExtension>
     <Assembly>WindowsAppSDK.Cpp.Extension.Dev17, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null</Assembly>
     <FullClassName>WindowsAppSDK.TemplateUtilities.NuGetPackageInstaller</FullClassName>
   </WizardExtension>
-  <WizardData>
-    <MinSupportedVersion>10.0.17763.0</MinSupportedVersion>
-    <SkipXamlCompilerCheck>true</SkipXamlCompilerCheck>
-  </WizardData>
 </VSTemplate>

dev/Templates/Source/ProjectTemplates/Desktop/CppWinRT/PackagedApp/WinUI.Desktop.CppWinRT.PackagedApp.vstemplate

@@ -27,5 +27,18 @@
       <ProjectTemplateLink ProjectName="$projectname$ (Package)" CopyParameters="true">WapProj\WinUI.Desktop.CppWinRT.WapProj.vstemplate</ProjectTemplateLink>
       <ProjectTemplateLink ProjectName="$projectname$" CopyParameters="true">BlankApp\WinUI.Desktop.CppWinRT.BlankApp.vstemplate</ProjectTemplateLink>
     </ProjectCollection> 
-  </TemplateContent>   
+  </TemplateContent>
+  <WizardExtension>
+    <!-- Generates Publisher name for appxmanifest -->
+    <Assembly>Microsoft.VisualStudio.WinRT.TemplateWizards, Version=16.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a</Assembly>
+    <FullClassName>Microsoft.VisualStudio.WinRT.TemplateWizards.UpdatePublisherInManifestWizard</FullClassName>
+  </WizardExtension>
+  <WizardExtension>
+    <Assembly>Microsoft.VisualStudio.Universal.TemplateWizards, Version=16.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a</Assembly>
+    <FullClassName>Microsoft.VisualStudio.Universal.TemplateWizards.PlatformVersion.Wizard</FullClassName>
+  </WizardExtension>
+  <WizardData>
+    <MinSupportedVersion>10.0.17763.0</MinSupportedVersion>
+    <SkipXamlCompilerCheck>true</SkipXamlCompilerCheck>
+  </WizardData>
 </VSTemplate>

dev/Templates/VSIX/build-local-VSIX-package/Build-VSIX-Local.ps1

@@ -49,6 +49,10 @@
 .PARAMETER SkipRestore
     Skip NuGet restore (useful if you've already restored).
 
+.PARAMETER MsBuildVersion
+    Visual Studio version to target for MSBuild. Default: 17 (Visual Studio 2022).
+    Set to 18 for Visual Studio 2026.
+
 .EXAMPLE
     .\Build-VSIX-Local.ps1
     # Build the LocalDev VSIX (default). Then install with .\Install-LocalDev-VSIX.ps1
@@ -82,7 +86,10 @@ param(
 
     [string]$OptionalVSIXVersion = "",
 
-    [switch]$SkipRestore
+    [switch]$SkipRestore,
+
+    [ValidateSet(17, 18)]
+    [double]$MsBuildVersion = 17
 )
 
 Set-StrictMode -Version 2.0
@@ -122,9 +129,10 @@ function Find-MSBuild {
         exit 1
     }
 
-    $msbuildPath = & $vswherePath -latest -requires Microsoft.Component.MSBuild -find "MSBuild\**\Bin\MSBuild.exe" 2>$null | Select-Object -First 1
+    $range = '[{0},{1})' -f $MsBuildVersion, ($MsBuildVersion + 1)
+    $msbuildPath = & $vswherePath -version $range -requires Microsoft.Component.MSBuild -find "MSBuild\**\Bin\MSBuild.exe" 2>$null | Select-Object -First 1
     if (-not $msbuildPath -or -not (Test-Path $msbuildPath)) {
-        Write-Err "MSBuild.exe not found. Please install Visual Studio 2022+ with the '.NET desktop development' workload."
+        Write-Err "MSBuild.exe not found. Please install Visual Studio $MsBuildVersion with the '.NET desktop development' workload."
         exit 1
     }
 
@@ -420,6 +428,44 @@ function Invoke-MSBuildBuild {
     }
 }
 
+function Test-VsixContainsTemplates {
+    param(
+        [string]$Path
+    )
+
+    Add-Type -AssemblyName System.IO.Compression.FileSystem
+
+    $archive = [System.IO.Compression.ZipFile]::OpenRead($Path)
+    try {
+        $projectTemplates = @(
+            $archive.Entries | Where-Object {
+                $_.FullName.StartsWith("ProjectTemplates/", [System.StringComparison]::OrdinalIgnoreCase) -and
+                $_.FullName.EndsWith(".vstemplate", [System.StringComparison]::OrdinalIgnoreCase)
+            }
+        )
+        $itemTemplates = @(
+            $archive.Entries | Where-Object {
+                $_.FullName.StartsWith("ItemTemplates/", [System.StringComparison]::OrdinalIgnoreCase) -and
+                $_.FullName.EndsWith(".vstemplate", [System.StringComparison]::OrdinalIgnoreCase)
+            }
+        )
+
+        if ($projectTemplates.Count -eq 0 -or $itemTemplates.Count -eq 0) {
+            Write-Err "VSIX template validation failed: $Path"
+            Write-Err "  Project templates: $($projectTemplates.Count)"
+            Write-Err "  Item templates   : $($itemTemplates.Count)"
+            Write-Err "The selected Visual Studio/MSBuild toolset may not support packaging these templates."
+            return $false
+        }
+
+        Write-Step "Verified templates in $($archive.Entries.Count)-entry VSIX: $($projectTemplates.Count) project, $($itemTemplates.Count) item"
+        return $true
+    }
+    finally {
+        $archive.Dispose()
+    }
+}
+
 function Copy-VsixOutput {
     param(
         [string]$DeploymentType
@@ -446,6 +492,10 @@ function Copy-VsixOutput {
     foreach ($vsix in $vsixFiles) {
         if (-not $seen.ContainsKey($vsix.Name)) {
             $seen[$vsix.Name] = $vsix
+            if (-not (Test-VsixContainsTemplates -Path $vsix.FullName)) {
+                exit 1
+            }
+
             # Rename to include version: WindowsAppSDK.Cs.Extension.Dev17.Component.vsix
             #   -> WindowsAppSDK.Cs.Extension.Dev17.Component.99.2026.0416.1640.vsix
             $newName = $vsix.BaseName + ".$OptionalVSIXVersion.vsix"

dev/Templates/VSIX/build-local-VSIX-package/build-install-localdev-vsix.ps1

@@ -26,6 +26,10 @@
 .PARAMETER UninstallFirst
     Run VSIXInstaller /uninstall before installing for a clean reinstall.
 
+.PARAMETER MsBuildVersion
+    Visual Studio version to target for MSBuild. Default: 17 (Visual Studio 2022).
+    Set to 18 for Visual Studio 2026.
+
 .EXAMPLE
     .\build-install-localdev-vsix.ps1
     # Build + install LocalDev C# + C++ to all VS 17+.
@@ -44,7 +48,10 @@ param(
 
     [string]$VsVersionRange = '[17.0,)',
 
-    [switch]$UninstallFirst
+    [switch]$UninstallFirst,
+
+    [ValidateSet(17, 18)]
+    [double]$MsBuildVersion = 17
 )
 
 Set-StrictMode -Version 2.0
@@ -86,7 +93,7 @@ if ($SkipBuild) {
     }
     Push-Location $scriptDir
     try {
-        & $buildScript -Deployment LocalDev
+        & $buildScript -Deployment LocalDev -MsBuildVersion $MsBuildVersion
         if ($LASTEXITCODE -ne 0) {
             Write-Err "Build-VSIX-Local.ps1 exited with code $LASTEXITCODE"
             exit $LASTEXITCODE