Hello all.

Project specifics: Visual Studio 2005  C#  Addin (under XP SP2)

I am having problems casting an project object from Project to VCProject. I
know it's a C++ project because I created a test one. When I try to cast it,
I get an E_NOINTERFACE exception with the following message:

"Unable to cast COM object of type 'System.__ComObject' to interface type
'Microsoft.VisualStudio.VCProjectEngine.VCProject'. This operation failed
because the QueryInterface call on the COM component for the interface with
IID '{238B5174-2429-11D7-8BF6-00B0D03DAA06}' failed due to the following
error: No such interface supported (Exception from HRESULT: 0x80004002
(E_NOINTERFACE))."

Thie code is structured so that there is delegate registered to handle the
OnOpened event:

// ********************************

public void OnConnection(object application, ext_ConnectMode connectMode,
object addInInst, ref Array custom)
       {
           _applicationObject = (DTE2)application;
           _addInInstance = (AddIn)addInInst;

           solutionEvents = _applicationObject.Events.SolutionEvents;
           solutionEvents.Opened += new
_dispSolutionEvents_OpenedEventHandler(UpDateSolSettings);
       }
// *********************************

The handler is supposed to modify attributes of all the VCProjects of the
solution:

// *********************************

private void UpDateSolSettings()
       {
           const string PROJECT_KIND_CPLUSPLUS_PROJECT =
"{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}";
           VCConfiguration conf;
           try
           {
               string strBaseDir = GetBaseDir();
               if (null != strBaseDir)
               {
                   foreach (Project proj in
_applicationObject.Solution.Projects)
                   {
                       if (proj.Kind == PROJECT_KIND_CPLUSPLUS_PROJECT)
                       {
                           VCProject vcproj = (VCProject)proj; //
<*********   THE EXCEPTION IS THROWN HERE.
                           IVCCollection Confs =
(IVCCollection)vcproj.Configurations;
                           for (int iConf = 0, nConf = Confs.Count; iConf <
nConf; iConf++)
                           {
                               conf = (VCConfiguration)Confs.Item(iConf);
                               conf.IntermediateDirectory = strBaseDir +
@"\obj\win32\$(TargetName)";
                           }
                       }
                   }
               }
           }
           catch(Exception e)
           {
               MessageBox.Show("Error: " + e.Message, "Error while
processing sol file.", MessageBoxButtons.OK, MessageBoxIcon.Warning);
           }
       }

// *********************************

Again, I am certain the solution only one project, and it's a VC++ project,
so the "proj" object should have the VCProject interface implemented.

Any ideas on what could be going on?

Any help greatly appreciated.

Regards,

Luis Bascones