How can I get the symbols of members defined in a .g.cs file using Roslyn?

Question

Given an INamedTypeSymbol of a WPF Window, I can't seem to obtain a ISymbol for the members that are defined in XAML (and are then compiled as part of the auto-generated .g.cs file).

To reproduce the problem I'm having,

1. Create a new blank WPF application in Visual Studio
2. Add <TextBlock Name="MyTextBlock"/> to MainWindow.xaml

3. Put the following code in the MainWindow.xaml.cs:

   public MainWindow()
   {
       InitializeComponent();
       var comp = CSharpCompilation.Create("My Compilation");
       comp = comp.AddReferences(MetadataReference.CreateFromFile(GetType().Assembly.Location));
       INamedTypeSymbol mainWindow = comp.GetTypeByMetadataName(GetType().FullName);
       var members = mainWindow.GetMembers();
       Debug.Assert(members.FirstOrDefault(m => m.Name == "MyTextBlock") != null) ;
   
   }
   

   As you can see, the assertion fails, and I cannot seem to find the ISymbol that represents the "MyTextBlock" member field.

Answer 1

This happens because Roslyn does not import private members of types from metadata. If you add x:FieldModifier="public" to your TextBlock it works as expected.

This has nothing to do with WPF, or generated symbols in .g.cs files.