Q241862: BUG: ClassWizard Omits Methods with BYTE or BYTE* As Parameters
Article: Q241862
Product(s): Microsoft C Compiler
Version(s): winnt:4.0,4.1,4.2,5.0,6.0
Operating System(s):
Keyword(s): kbAutomation kbCOMt kbCtrl kbMFC kbVC400bug kbVC500bug kbVC600bug kbClassWizard kbCompG
Last Modified: 02-MAY-2001
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The information in this article applies to:
- The ClassWizard, included with:
- Microsoft Visual C++, 32-bit Editions, versions 4.0, 4.1
- Microsoft Visual C++, 32-bit Enterprise Edition, version 4.2
- Microsoft Visual C++, 32-bit Professional Edition, version 4.2
- Microsoft Visual C++, 32-bit Enterprise Edition, version 5.0
- Microsoft Visual C++, 32-bit Professional Edition, version 5.0
- Microsoft Visual C++, 32-bit Enterprise Edition, version 6.0
- Microsoft Visual C++, 32-bit Professional Edition, version 6.0
- Microsoft Visual C++, 32-bit Learning Edition, version 6.0
- The Component Gallery, included with:
- Microsoft Visual C++, 32-bit Editions, versions 4.0, 4.1
- Microsoft Visual C++, 32-bit Enterprise Edition, version 4.2
- Microsoft Visual C++, 32-bit Professional Edition, version 4.2
- Microsoft Visual C++, 32-bit Enterprise Edition, version 5.0
- Microsoft Visual C++, 32-bit Professional Edition, version 5.0
- Microsoft Visual C++, 32-bit Enterprise Edition, version 6.0
- Microsoft Visual C++, 32-bit Professional Edition, version 6.0
- Microsoft Visual C++, 32-bit Learning Edition, version 6.0
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SYMPTOMS
========
When generating wrapper classes for a COM server that has methods that take a
BYTE or BYTE* as a parameter, the MFC wizards do not generate code for these
methods. The wizard does place a comment in the wrapper class header file that
states that the method was not emitted due to an invalid return type or
parameter type. Following is the exact text:
// Operations
public:
// method 'PassByte' not emitted because of invalid return type or parameter type
BYTE and BYTE* are both OLE Automation compatible data types, thus this message
can be somewhat confusing.
CAUSE
=====
This is due to bugs in ClassWizard and Component Gallery not recognizing BYTE
and BYTE* as valid OLE Automation data types.
RESOLUTION
==========
You can add the methods that were omitted manually. For example, given a method
PassByte that takes a single BYTE parameter and another method PassBytePointer
that takes a single BYTE* parameter, you could add the following code to the
wrapper class in the wrapper class header file as follows:
// Operations
public:
// method 'PassByte' not emitted because of invalid return type or parameter type
void PassByte(BYTE byteVal);
// method 'PassBytePointer' not emitted because of invalid return type or parameter type
void PassBytePointer(BYTE *pbyteVal);
Next, you need to add the code to the wrapper class source file. Given the
example above, it should look like the following:
#define MY_VTS_UI1 "\x11"
//Do NOT use VTS_UI1. It has a value of "0x0F" which is incorrect.
//The correct value for VT_UI1 is 17 or 0x11
#define MY_VTS_PUI1 "\x51"
//Do NOT use VTS_PUI1. It has a value of "0x4F" which is incorrect.
//The correct value for VT_PUI1 is 81 or 0x51
void C_UserControl1::PassByte(BYTE byteVal)
{
static BYTE parms[] = MY_VTS_UI1; //please note that this is not VTS_UI1
DISPID dispid = 0x60030000;
InvokeHelper(dispid, DISPATCH_METHOD, VT_EMPTY, NULL, parms, byteVal);
}
void C_UserControl1::PassBytePointer(BYTE *pbyteVal)
{
static BYTE parms[] = MY_VTS_PUI1; //please note that this is not VTS_PUI1
DISPID dispid = 0x60030001; //notice that this is different!
InvokeHelper(dispid, DISPATCH_METHOD, VT_EMPTY, NULL, parms, pbyteVal);
}
It is important to note that you need to get the DISPIDs for the omitted methods
using a type library viewing tool. OLE/COM Object Viewer is one such tool. You
can access this tool from the Tools menu in Visual C++. In OLE/COM Object
Viewer, select the File menu and the View Typelib menu item. Next, find the .tlb
or .ocx file for the COM server and click Open. This opens a new window with a
tree control on the left side. Select the topmost item in the tree control and
you will see all of the methods on the right with their corresponding DISPID's.
A second important point is that VTS_UI1 and VTS_PUI1 are not used above. For
additional informationon this bug, click the article number below to view the
article in the Microsoft Knowledge Base:
Q242588 VTS_U1 and VTS_PUI1 are Defined Incorrectly in AfxDisp.h Header File
STATUS
======
Microsoft has confirmed this to be a bug in the Microsoft products listed at the
beginning of this article.
MORE INFORMATION
================
Steps to Reproduce Behavior
---------------------------
1. Create a new Visual Basic ActiveX control.
2. Add one method that takes a BYTE parameter. For example:
Public Sub PassByte(ByVal b as Byte)
End Sub
3. Build the control.
4. Create a new MFC Dialog based application.
5. Add the Visual Basic control that was generated in step 3 using Component
Gallery. Do this by going to the Project menu, select Add Components and
Controls, and then selecting Registered ActiveX Controls.
6. After you select the Visual Basic control and click OK, Component Gallery
presents the Confirm Classes dialog. Click OK on the Confirm Classes dialog
box to generate the wrapper code.
To see the missing method, open up the generated wrapper class header file. You
should see the text that states the method PassByte was not emitted because of
invalid return type or parameter type.
REFERENCES
==========
For additional information, click the article number below to view the article
in the Microsoft Knowledge Base:
Q242588 VTS_U1 and VTS_PUI1 are Defined Incorrectly in AfxDisp.h Header File
In MSDN documentation, refer to CWnd::InvokeHelper and
COleDispatchDriver::InvokeHelper for more information on the parameters for
these functions.
Additional query words: automation wrapper wizard code
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Keywords : kbAutomation kbCOMt kbCtrl kbMFC kbVC400bug kbVC500bug kbVC600bug kbClassWizard kbCompGallery kbDSupport kbGrpDSMFCATL
Technology : kbVCsearch kbAudDeveloper kbClassWizard
Version : winnt:4.0,4.1,4.2,5.0,6.0
Issue type : kbbug
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