Why? --> Unable to cast COM object of type 'System.__ComObject' to interface type 'Microsoft.VisualStudio.Shell.Interop.ITrackSelection'.

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C#

Visual-Studio

Hello anyone,

I run in a confusing problem.

Within my Editor's pane of my custom VisualStudio Package I am getting following error message:

Unable to cast COM object of type 'System.__ComObject' to interface type 'Microsoft.VisualStudio.Shell.Interop.ITrackSelection'. This operation failed because the QueryInterface call on the COM component for the interface with IID '{6D5140C5-7436-11CE-8034-00AA006009FA}' failed due to the following error: No such interface supported (Exception from HRESULT: 0x80004002 (E_NOINTERFACE)).

The locals are:
+ (ISelectionContainer)selContainer {Microsoft.VisualStudio.Shell.SelectionContainer} Microsoft.VisualStudio.Shell.Interop.ISelectionContainer {Microsoft.VisualStudio.Shell.SelectionContainer}


+selContainer {Microsoft.VisualStudio.Shell.SelectionContainer} Microsoft.VisualStudio.Shell.SelectionContainer

-track COM Object Microsoft.VisualStudio.Shell.Interop.ITrackSelection {System.__ComObject}



The caller code follows, actualy this code part can be found on the web several times, I just copied and pasted it:

private ITrackSelection TrackSelection {
   get {
       if (trackSel == null)
           trackSel = GetService(typeof(STrackSelection)) as ITrackSelection;
       return trackSel;
   }
}

public void UpdateSelection()
{
    ITrackSelection track = TrackSelection;
    if (track != null)
        track.OnSelectChange((ISelectionContainer)selContainer);
}

The most confusing point is, that within my constructor everything works fine! The interface can be queried and has been excuted, but any following call fails.