We normally dont do this
but we override the OnOK but that should not be the cause of the problem. You are treating IDOK as a normal button and call dialog should be called.
Is it that CallDialog is not getting called then follow this steps
Make a dialog based MFC exe application
Copy the following line in the message map
Now add the CallDialog function in .h as follows
afx_msg void CallDialog();
I think this should do the job