Hi  All,  The VC++ 8.0 program below compiles in Visual_Studio_2005.
It's attempting to automate Visual_Studio_2005 to do:

 DTE.ItemOperations.OpenFile("C:\__\X\In.TXT")
 
Invoke(OpenFile)  returns DISP_E_MEMBERNOTFOUND, 0x80020003.
C:\__\X\In.TXT does exist.

Similar code works fine when I automate Excel, so why doesn't it work in VS ?
....+.+.+

#pragma warning( disable:  4127 4244 4305 4430 4508 4701 4702 4706 4996  )
#undef _DEBUG
#define UNICODE
#define _WIN32_WINNT 0x0501
#define WIN32_LEAN_AND_MEAN
#include <Windows.H>
#include <StdIO.H>
#include <Ole2.H>

#define  Loop( N )  int J = - 1, LLL = N ; while ( ++ J < LLL )
#define  Str  swprintf
#define  Rel( X ) ( ! X ? 0 : (short) X == -1 ? X = 0 : ( X->Release(), X = 0))
#define FrV( X )  \
 ( X.vt == VT_DISPATCH ? 0 : VariantClear( & X ), memset( & X, 0, sizeof X ) )

typedef unsigned char  uchar ;  typedef unsigned short  ushort ;  
typedef unsigned long  ulong ;  typedef unsigned int  uint ;  
typedef uchar  * _LnP ;  typedef char  * __LnP ;
typedef wchar_t  * LnP ;  typedef  LnP  * LnA ;  
const int Sz_Ptr = sizeof( _LnP ), Sz_Char = sizeof ( wchar_t );

typedef IDispatch  * OleT ;  OleT VS ;  VARIANT OleRV, Var, Var2 ;
wchar_t  Error [ 400 ];

_Call…( int IdenType, OleT Container, LnP  Macro, int  Cnt_Params, _LnP SP ) {
 FrV( OleRV );  HRESULT rv ;
 if ( ! Container || ( short ) Container == -1 )  return ;
 DISPID  IdenID = 0 ;
 rv = Container->GetIDsOfNames( IID_NULL, & Macro
 , 1, LOCALE_USER_DEFAULT, & IdenID );
 if ( FAILED( rv ) ) {
   Str( Error, L"0x%08lx, Was _%s_ misspelled ?"
   , rv, Macro);  return ;  }
 VARIANT  * B_Args = new  VARIANT [ Cnt_Params + 1 ]
 , * P_Args = B_Args + Cnt_Params ;
 Loop( Cnt_Params )
   * -- P_Args = * ( VARIANT * ) SP, SP += sizeof VARIANT ;
 DISPPARAMS  ParamList = { 0 };  
 ParamList.cArgs = Cnt_Params ;  ParamList.rgvarg = B_Args ;
 if ( IdenType & DISPATCH_PROPERTYPUT ) {  ParamList.cNamedArgs = 1 ;  
   DISPID dispidNamed = DISPID_PROPERTYPUT;
   ParamList.rgdispidNamedArgs = & dispidNamed ;  }
 rv = Container->Invoke( IdenID, IID_NULL
 , LOCALE_SYSTEM_DEFAULT, IdenType, & ParamList, & OleRV, 0, 0 );
 delete [] B_Args ;
 if ( FAILED( rv ) )
   Str( Error, L"0x%08lx, _%s_ Needs more/less/better parameters ?"
   , rv, Macro );
 if ( rv < 0 || OleRV.vt <= 1 || OleRV.vt == VT_ERROR )  FrV( OleRV );  }

Call( OleT Container, LnP  Macro ) {  
 _Call…( DISPATCH_METHOD, Container, Macro, 0, 0 );  }

Call…( OleT Container, LnP  Macro, int Cnt_Params, ...) {
 _Call…( DISPATCH_PROPERTYPUT
 , Container, Macro, Cnt_Params, ( _LnP ) & Cnt_Params + Sz_Ptr );  
 FrV( Var );  }

Call…RV( OleT Container, LnP  Macro, int Cnt_Params, ... ) {
 _Call…( DISPATCH_PROPERTYGET
 , Container, Macro, Cnt_Params, ( _LnP ) & Cnt_Params + Sz_Ptr );
 FrV( Var );  }

__stdcall WinMain( HINSTANCE, HINSTANCE, LPSTR, int ) {
 CoInitialize( 0 );  CLSID  clsid ;  
 CLSIDFromProgID( L"VisualStudio.DTE", & clsid );  
 IUnknown  * _VS ;
 GetActiveObject( clsid, 0, ( IUnknown * * ) & _VS );  VS = 0;
 if ( _VS )  _VS->QueryInterface( IID_IDispatch, (void **) & VS );
 if ( ! VS ) {   Rel( _VS );  return ; }
 //  DTE.ItemOperations.OpenFile("C:\__\X\In.TXT")
 OleT  ItemOperations ;
 Call…RV( VS, L"ItemOperations", 0 );  
 if ( ! ( ItemOperations = OleRV.pdispVal ) )  goto Clean_Up ;

 Var.vt = VT_BSTR;  Var.bstrVal = SysAllocString( L"C:\\__\\X\\In.TXT" );
 Call…RV( ItemOperations, L"OpenFile", 1, Var );  
 //  OleRV is now blank,  Error:  DISP_E_MEMBERNOTFOUND, 20003

 Clean_Up:  Rel( VS ); Rel( _VS );
}