Hi there, It is really very easy to implement events in your COM DLL. whenever u insert any ATL object in your ATL project, using ATL Object Wizard. ATL Object Wizard property box pop ups, go to attribute tab and select the check box "Support connection points" this will create an dispinterface which can contain ur event methods. now u have to simply add method in this interface. compile ur code . and then in class view select ur class which is going to implement this evennt interface, right click on it and add implement Connection point. a dialog box will pou up , select that event interface and click OK. Now just fire this event method from ur code. In ur VB client when just select ur Dll object . and it will list out all event methods implemented by ur dll Object. u can simply slect those event method and can code whatever u like. :) Abhishek Srivastava Software Engg (VC++) India ,Noida Mobile no 9891492921 :)

You are defining an incorrect handling function in your CMyAppDlg, the right way to do so is: // in MyAppDlg.h class CMyAppDlg : public CDialog { // ... ... afx_msg LRESULT OnToggle(WPARAM wParam, LPARAM lParam); // ... ... } // in MyAppDlg.cpp ON_MESSAGE(TOGGLE, OnToggle) LRESULT CMyAppDlg::OnToggle(WPARAM wParam, LPARAM lParam) { // ... ... return (LRESULT)0; } This will work fine.