CODEWITHSUNDEEP
c#.net-4.0imetadataimport
Paulie
Paulie

Reputation: 81

Problems with IMetaDataImport::ResolveTypeRef Method

I have my own debugger for .NET apps that uses IMetaDataImport interface

When I call ResolveTypeRef method, I always get NotImplementedException.

The definition of ResolveTypeRef is like this:

[ComImport]
[Guid("....")] //a valid GUID
[InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
[CLSCompliant(false)]
public interface IMetaDataImport {
  void ResolveTypeRef(
    [ComAliasName("mdTypeRef")] mdToken tr,
    [ComAliasName("REFIID")] ref Guid riid,
    [ComAliasName("IUnknown**"), Out, MarshalAs(UnmanagedType.IUnknown)] out object ppIScope,
    [ComAliasName("mdTypeDef*"), Out] out mdToken ptd
  );
  // ... other methods from IMetaDataImport
}

The method calling:

metadataImport.ResolveTypeRef(typeRefToken, ref metadataImportGuid, out metadataObject, out typeDefToken)

Typically, the method should resolve type System.Exception or System.SystemException.

The problem occured when I moved app from .NET 3.5 to .NET 4.

Thanks for the answers!

Upvotes: 5

Views: 642

Answers (2)

lordmilko
lordmilko

Reputation: 171

If you actually try and step into the method ResolveTypeRef, it seems you actually end up at SymMethod::GetSourceStartEnd which is what is returning E_NOTIMPL. Furthermore, if you have a look at the vtable in IDA, as far as I can see the method ResolveTypeRef doesn't even exist on IMetaDataImport/2's vtable; rather, it is a method on CordbModule, however evidently isn't actually exposed in the ICorDebugModule interface.

In any case, the conclusion here appears to be that Microsoft's documentation/header files are out of date with the actual implementation

Upvotes: 0

Paulie
Paulie

Reputation: 81

Uff, I finally get rid of this ... The solution is not call ResolveTypeRef, but create your own method to resolve type: 

  mdToken ptkResScope;
  uint len;
  metadataImport.GetTypeRefProps(typeRef, out ptkResScope, null, 0, out len);
  StringBuilder sb = new StringBuilder((int)len);
  metadataImport.GetTypeRefProps(typeRef, out ptkResScope, sb, len, out len);
  string className = sb.ToString();
  foreach (loadedModule ) {   // this is quite tricky part ...     
    metadataImportForLoadedModule = GetMetaDataImportForModule(loadedModule);
    metadataImportForLoadedModule.FindTypeDefByName(className, mdToken.Nil, out typeDef);
    if ( typeDef.IsNonNil(CorTokenType.mdtTypeDef) ) {
      return typeDef;
      }
    }

The idea comes from David Broman's CLR Profiling API Blog: Metadata Tokens, Run-Time IDs, and Type Loading (really good reading if you are interested in MetaDataImport).

Upvotes: 3

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