Question

In my main window, after clicking a menu item, a dialog box appears which asks the user for input. That input is then to be retrieved.

Here is the resource file for the dialog box:

//
// Dialog resources
//
IDD_PID DIALOG 0, 0, 158, 84
STYLE DS_3DLOOK | DS_CENTER | DS_MODALFRAME | DS_SHELLFONT | WS_CAPTION | WS_VISIBLE | WS_POPUP
FONT 8, "MS Sans Serif"
{
    PUSHBUTTON  "&Ok", ID_PID_RET, 14, 60, 58, 14
    PUSHBUTTON  "&Cancel", ID_PID_CANCEL, 86, 60, 52, 14
    CTEXT       "Enter the PID of the process", -1, 32, 16, 91, 15, SS_CENTER
    CONTROL     "", ID_PID_INPUT, RICHEDIT_CLASS, WS_TABSTOP | WS_BORDER | ES_AUTOHSCROLL, 47, 33, 59, 14, WS_EX_CLIENTEDGE
}

Here is the WindowProc where the dialog is used:

//
// Message handling for main window
//
LRESULT CALLBACK WindowProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    switch(message)
    {
    case WM_COMMAND:
        switch (LOWORD(wParam))
        {
        case ID_FILE_PID:
            int choice = DialogBox(thishInstance, MAKEINTRESOURCE(IDD_PID), hWnd, AboutDlgProc);
            if (choice == ID_PID_RET)
            {
                HWND temp = GetDlgItem(hWnd, ID_PID_INPUT);
                HRESULT HR = GetLastError();
                SendMessage(temp, WM_GETTEXT, sizeof(buff), (LPARAM)&buff);

                [...]
            }
            break;
        }
    }
}

I am a little uncertain about how it works when I try to get the HWND if I create the windows in the resource files. This should work somehow, right? hWnd is managing the dialog box, and ID_PID_RET is the control ID of the Rich Edit box for user input, so I don’t know why GetDlgItem fails. It returns “Control ID not found”, but it is defined in my resource.h. Any ideas?

Answer 1

DialogBox only returns after EndDialog has been called and the dialog has been destroyed. The dialog no longer exists when you call GetDlgItem. You can use DialogBoxParam and pass in a buffer/struct/class for the dialog to fill in with the content of the Rich Edit field, before it calls EndDialog.