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How to Process Notification Messages

  • Article

A property sheet sends WM_NOTIFY messages to retrieve information from the pages and to notify the pages of user actions.

The lParam parameter of the message is the address of an NMHDR structure, which contains the handle to the property sheet dialog box, the handle to the page dialog box, and a notification code. The page must respond to some notification messages by setting the DWL_MSGRESULT value of the page to either TRUE or FALSE.

What you need to know

Technologies

Prerequisites

  • C/C++
  • Windows User Interface Programming

Instructions

Process Notification Messages

The following example is a code fragment from the dialog box procedure for a page. It shows how to process the PSN_HELP notification code.

case WM_NOTIFY:

    switch (((NMHDR FAR *) lParam)->code) 
    {
    case PSN_HELP:
        {
         
        char szBuf[FILE_LEN]; // Buffer for name of Help file

        // Display Help for the font properties page.
        LoadString(g_hinst, IDS_HELPFILE, &szBuf, sizeof(szBuf)/sizeof(szBuf[0]));
        WinHelp(((NMHDR FAR *)lParam)->hwndFrom, &szBuf, HELP_CONTEXT, IDH_FONT_PROPERTIES);                
        
        break;
        
         }
         
        // Process other property sheet notifications here.
    }

Using Property Sheets

Windows common controls demo (CppWindowsCommonControls)