BUG: COMException getting DocComment of method of generic base class

Author:	Carlos J. Quintero (Microsoft MVP)	Applies to:	Microsoft Visual Studio 2010
Date:	August 2011

Introduction

When trying to get the EnvDTE80.CodeFunction2.DocComment property of a method of a generic base class, you get a COMException when using C# and Visual Studio 2010. This didn't happen in Visual Studio 2008 or 2005, and it doesn't happen using VB.NET with Visual Studio 2010.

More Information

Steps to reproduce the problem:

• Create a macro with the following code:

Language: VB.NET

Copy Code (IE only)

Sub Macro1()

        Dim derivedCodeClass2 As EnvDTE80.CodeClass2
        Dim baseCodeClass2 As EnvDTE80.CodeClass2
        Dim someMethodOfBaseClass As EnvDTE80.CodeFunction2

        Try

            derivedCodeClass2 = CType(DTE.ActiveDocument.ProjectItem.FileCodeModel.CodeElements.Item(1), EnvDTE80.CodeClass2)

            baseCodeClass2 = CType(derivedCodeClass2.Bases.Item(1), EnvDTE80.CodeClass2)

            someMethodOfBaseClass = CType(baseCodeClass2.Members.Item(1), EnvDTE80.CodeFunction2)

            System.Windows.Forms.MessageBox.Show(someMethodOfBaseClass.DocComment)

        Catch ex As Exception

            System.Windows.Forms.MessageBox.Show(ex.ToString)

        End Try

End Sub

• Create a C# project with Visual Studio 2010 and paste this code in the Class1.cs file:

Language: C#

Copy Code (IE only)

public class DerivedClass: BaseClass<int>
{
}

public class BaseClass<T>
{
   /// <summary>
   /// SomeMethod()
   /// </summary>
   public virtual void SomeMethod()
   {
   }
}

• Execute the macro when the Class1.cs file is active. You get a "System.Runtime.InteropServices.COMException (0x80004005): Error HRESULT E_FAIL has been returned from a call to a COM component".

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