PRB: Passing Parameters By Reference to a VC COM Object

MORE INFORMATION

Steps to Reproduce Behavior

1. Create an ATL DLL Project called "ByRefProj."
2. Insert an ATL Object named "ByRefObj."
3. Add and implement the method.
   1. Add a method with the following information:

            Method Name: ByRefMethod
            Parameters : [out]BSTR* bstrVal
        
      						

   2. Implement the method as follows:

      STDMETHODIMP CByRefObj::ByRefMethod( BSTR* bstrVal )
      {
        CComBSTR bstrRtnVal = L"This variable is passed by Reference";
        *bstrVal = bstrRtnVal.Detach();
        return S_OK;
      }
      						

4. Create an Active Server Pages (ASP) page that calls this method:

   <%
     Dim objTest, strByRefVal
     Set objTest = Server.CreateObject("ByRefProj.ByRefObj")
     objTest.ByRefMethod strByRefVal
   %>

5. Run ASP, and the following error occurs:
   Microsoft VBScript runtime error '800a000d'
   Type mismatch: 'ByRefMethod'

1. Change the IDL declaration in the ByRefProj.idl file to:

   [id(1), helpstring("method ByRefMethod")] HRESULT ByRefMethod([out] VARIANT* vVal); 
   						

2. Change the method in the .h and .cpp file. Change the method as follows:

   // Where m_bstr is a BSTR member of SomeComObject.
   vVal->vt = VT_BSTR;
   vVal->bstrVal = m_bstr.Copy();
   						

3. Recompile.