How to Send & Receive a WM_USER Message? 1

[panioti]

I want to send a user-defined message, and process it in the destination Class.

(CWnd*) pDest->SendMessage(WM_USER,0,0);

This compiles with no error and will presumably send the msg.

I don't know how to map the msg at the receiving class.
Class Wizard doesn't list WM_USER as a message ID, so I'll have to code it myself.

 

[PerFnurt]

>Class Wizard doesn't list WM_USER as a message ID, so I'll have to code it myself.

Indeed.

First of all, I'd recommend to base your user defined messages on WM_APP rather that WM_USER because MFC uses WM_USER stuff. To be sure you have unique message id's use WM_APP.

Anyway...

In the .h file

class CMyWnd  // ... etc
{
    //{{AFX_MSG(CMyWnd)
    //  ...
    afx_msg LRESULT OnCallSomeMethod(WPARAM, LPARAM);
    //}}AFX_MSG
    DECLARE_MESSAGE_MAP()

In the .cpp file:

BEGIN_MESSAGE_MAP(CMyWnd, CWnd)
    //{{AFX_MSG_MAP(CMyWnd)
    ...
    ON_MESSAGE(MYMESS_CALL_SOME_METHOD, OnCallSomeMethod)
    //}}AFX_MSG_MAP
END_MESSAGE_MAP()

LRESULT CMyWnd::OnCallSomeMethod(WPARAM wp, LPARAM lp)
{
    // Whatever...
    return 0;
}

Somewhere accessible:

#define MYMESS_CALL_SOME_METHOD (WM_APP + 1)

// or make it a const unsigned int if you want to avoid macros

Call it

theWnd->SendMessage(MYMESS_CALL_SOME_METHOD , 0, 0):

(i prefer typed constants rather than macros, hence the static const)

/Per
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