error CS7069: Reference to type 'DispatcherQueue' claims it is defined in 'Microsoft.WinUI', but it could not be found

Question

I'm following this doc to unit test a WinUi 3 project using MSTest.

https://devblogs.microsoft.com/ifdef-windows/winui-desktop-unit-tests/

I had this build error after edited OnLaunched method from App.xaml.cs file:

error CS7069: Reference to type 'DispatcherQueue' claims it is defined in 'Microsoft.WinUI', but it could not be found.

App.xaml.cs:

using Microsoft.VisualStudio.TestTools.UnitTesting.AppContainer;
...
protected override void OnLaunched(Microsoft.UI.Xaml.LaunchActivatedEventArgs args)
{
    Microsoft.VisualStudio.TestPlatform.TestExecutor.UnitTestClient.CreateDefaultUI();

    m_window = new MainWindow();

    // Ensure the current window is active
    m_window.Activate();

    UITestMethodAttribute.DispatcherQueue = m_window.DispatcherQueue; //Error

    // Replace back with e.Arguments when https://github.com/microsoft/microsoft-ui-xaml/issues/3368 is fixed
    Microsoft.VisualStudio.TestPlatform.TestExecutor.UnitTestClient.Run(Environment.CommandLine);
}

Here is issue about the same error. https://github.com/microsoft/testfx/issues/993

What does this solution mean? I still don't know how to resolve this error.

DispatcherQueue is moved to Microsoft.UI.Dispatching namespace. You might want to check your references.

Environment:

<Project Sdk="Microsoft.NET.Sdk">
  <PropertyGroup>
    <OutputType>WinExe</OutputType>
    <TargetFramework>net6.0-windows10.0.19041.0</TargetFramework>
    <TargetPlatformMinVersion>10.0.17763.0</TargetPlatformMinVersion>
    <RootNamespace>WelcomeScreen</RootNamespace>
    <ApplicationManifest>app.manifest</ApplicationManifest>
   
    <Platforms>x86;x64;ARM64</Platforms>
    <RuntimeIdentifiers>win10-x86;win10-x64;win10-arm64</RuntimeIdentifiers>
    <PublishProfile>win10-$(Platform).pubxml</PublishProfile>
    <UseWinUI>true</UseWinUI>
    <EnableMsixTooling>true</EnableMsixTooling>
  </PropertyGroup>
  <ItemGroup>
    <AppxManifest Include="Package.appxmanifest">
      <SubType>Designer</SubType>
    </AppxManifest>
  </ItemGroup>
  <ItemGroup>
    <ProjectCapability Include="TestContainer" />
  </ItemGroup>

  <ItemGroup>
    <PackageReference Include="CommunityToolkit.Mvvm" Version="8.2.2" />
    <PackageReference Include="Microsoft.Extensions.DependencyInjection" Version="8.0.0" />
    <PackageReference Include="Microsoft.WindowsAppSDK" Version="1.4.230913002" />
    <PackageReference Include="Microsoft.Windows.SDK.BuildTools" Version="10.0.22621.755" />
    <PackageReference Include="Microsoft.Xaml.Behaviors.WinUI.Managed" Version="2.0.9" />
    <Manifest Include="$(ApplicationManifest)" />
  </ItemGroup>

  <ItemGroup>
    <PackageReference Include="MSTest.TestAdapter">
      <Version>3.2.2</Version>
    </PackageReference>
    <PackageReference Include="MSTest.TestFramework">
      <Version>2.2.4</Version>
    </PackageReference>
    <PackageReference Include="Microsoft.TestPlatform.TestHost">
      <Version>17.10.0-preview-24080-01</Version>
      <ExcludeAssets>build</ExcludeAssets>
    </PackageReference>
  </ItemGroup>

Answer 1

It seems that there's been some break changes since that blog was published. Updating the NuGet packages to the latest version should fix that compile error.

<ItemGroup>
  <PackageReference Include="MSTest.TestAdapter">
    <Version>3.2.2</Version>
  </PackageReference>
  <PackageReference Include="MSTest.TestFramework">
    <Version>3.2.2</Version>
  </PackageReference>
  <PackageReference Include="Microsoft.TestPlatform.TestHost">
    <Version>17.9.0</Version>
    <ExcludeAssets>build</ExcludeAssets>
  </PackageReference>
</ItemGroup>