Wana add a message handler for your own custom message

Few days back I received an email asking a question, here is it all with my answer

Qst

Can you tell me  if I use the following

AfxGetMainWnd()->SendMessage(MY_MESSAGE, 0,(LPARAM) pValue);

The above message is sent to the parent window The message handler is

• LRESULT MyParent::OnMyMessage(WPARAM wParam, LPARAM lParam )
• {
•     *(int *) lParam = 123;
•             return 0;
• }

then can I make Message map of the form MY_MESSAGE and have a handler function OnMyMessage ? Since message maps are something that are provided by Windows API and they can be generated through Class Wizard where messages and their corresponding functions are already given. Ex WM_KEYDOWN with function OnKeyDown() Where should I map if (MY_MESSAGE) call OnMyMessage();

My Answer

As long as I understood the situation is you want to add a message handler for your own custom message.

#define WM_MYMESSAGE (WM_USER + 100)

in the header file just have this

afx_msg LRESULT OnMyMessage(WPARAM wParam, LPARAM lParam);

in cpp file do this

• BEGIN_MESSAGE_MAP(CMyWnd, CMyParentWndClass)
• ON_MESSAGE(WM_MYMESSAGE, OnMyMessage)
• END_MESSAGE_MAP()
• LRESULT MyParent::OnMyMessage( WPARAM wParam, LPARAM lParam )
• {
•     // do what ever you wnat to do
•     *(int *)lParam = 123;
•      return 0;
• }

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