Question and Answer Database FAQ2672C.txt Message handlers for ActiveX controls Category :ActiveX Platform :All Product :C++Builder 3.x Question: Why, when I have a VCL component, that has a message handler in it, does the assistant fail when creating the code and report errors from the message handler macros. How can I still use this message handler with my ActiveX? The message handler looks like (as it should): BEGIN_MESSAGE_MAP MESSAGE_HANDLER(WM_ERASEBKGND,TWMEraseBkgnd,WMEraseBkgnd) END_MESSAGE_MAP(TCustomControl) Answer: Change MESSAGE_HANDLER(WM_ERASEBKGND,TWMEraseBkgnd,WMEraseBkgnd) to VCL_MESSAGE_HANDLER(WM_ERASEBKGND,TWMEraseBkgnd,WMEraseBkgnd) This is necessary due to the fact that ATL has a macro defined as MESSAGE_HANDLER. Use of the VCL_ prefix works fine even if you don't try to convert to ActiveX. 7/2/98 10:32:32 AM
Last Modified: 01-SEP-99