Thread: Control message handling

  1. #1
    Registered User
    Join Date
    Feb 2006

    Control message handling

    Ok, I have created a button control during runtime, and I want to know how I can handle it. I tried using GetDlgItem() in many different ways but it doesn't work. My WM_CREATE message looks like this:

            case WM_CREATE:
                     HFONT hfDefault;
                     HWND hEdit;
                     HWND hButton;
                     hEdit = CreateWindowEx(WS_EX_CLIENTEDGE,
                                            WS_VISIBLE | WS_CHILD,
                     hButton = CreateWindowEx(0,
                                              WS_VISIBLE | WS_CHILD,
                     hfDefault = (HFONT)GetStockObject(DEFAULT_GUI_FONT);
    also, can someone explain to me how using the MAKELPARAM() macro and filling it in with false and 0 make a lparam appropriate for my message.
    Last edited by Homunculus; 02-04-2006 at 11:56 PM.

  2. #2
    int x = *((int *) NULL); Cactus_Hugger's Avatar
    Join Date
    Jul 2003
    Banks of the River Styx
    First, GetDlgItem() only works for Dialogs. (Duh.) Dialogs use WM_INITDIALOG message. So, are you using a dialog or a window? The above appears to be a window. If it's a dialog, I'd look up WM_INITDIALOG, and see I might perhaps create those controls in a resource file.

    Regardless of it is a window or a dialog, if the button is being created, all is good. To get a button "click", you can process the WM_COMMAND message. And bunch of controls will sent this whenever something happens to them, including buttons. The WM_COMMAND message contains a notification code, a handle to the window (button) that generated the message, and (possibly) the id of the control. (Usually in dialogs, where you know the ID and not the handle) Look up WM_COMMAND and BN_CLICKED, that should give what you want.
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  3. #3
    Join Date
    Jan 2002
    >>GetDlgItem() only works for Dialogs<<

    Actually, it's good for any window:
    Quote Originally Posted by msdn

    You can use the GetDlgItem function with any parent-child window pair, not just with dialog boxes.
    CProgramming FAQ
    Caution: this person may be a carrier of the misinformation virus.

  4. #4
    Registered User
    Join Date
    Feb 2006


    I thought I seen something like that on msdn =P. Well im going to go look up on BN_CLICKED and see what I can find, (I already tried putting something in case WM_COMMAND but haven't been to succesful)

  5. #5
    train spotter
    Join Date
    Aug 2001
    near a computer
    Remember that as you have declared the HWNDs for the conrols as non static in the callback that they will not retian their values after the WM_CREATE msg is processed.
    This means you will have to use the controls ID#, not HWND to find if that control has been used.

    You can use GET_WM_COMMAND_ID() from windowsx.h

    something like...

    case WM_COMMAND:
         switch(GET_WM_COMMAND_ID(wParam,lParam))//switch based on the controls ID#
                  case IDC_MAIN_BUTTON:
                      if( GET_WM_COMMAND_CMD( wParam, lParam)== BN_CLICKED)
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  6. #6
    Registered User
    Join Date
    Feb 2006

    You read my mind >.>

    That was one of my many questions I planned on asking in the future,thanks, When I was closing through my menu, I could hear my button making a message box and closing quickly... But everything is working perfectly since I changed my button to a static =D

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