Dynamically Disabling/Enabling a Control in a Dialog Box

ID: Q108896


The information in this article applies to:
  • The Microsoft Foundation Classes (MFC), included with:
    • Microsoft Visual C++ for Windows, 16-bit edition, versions 1.0, 1.5, 1.51, 1.52
    • Microsoft Visual C++, 32-bit Editions, versions 1.0, 2.0, 2.1, 4.0

This article demonstrates one way to disable or enable a dialog box control during the execution of a program with the Microsoft Foundation Classes (MFC). The dialog box uses a dialog box template created by App Studio.

To disable or enable a control in a dialog box, the following steps can be performed:

  1. Create a data member in the dialog box class that maps to a specific control (you can use Class Wizard to do this). For example:
    
          ...
          public:
          CButton     m_button;
          ... 


  2. Override CWnd::DoDataExchange(CDataExchange *pDX) in the dialog box class and call the appropriate DDX routine to hook the Windows control to the dialog class data member. For example:
    
          ...
          protected:
          virtual void DoDataExchange(CDataExchange* pDX);
          ...
    
          void CMyDlg::DoDataExchange(CDataExchange* pDX)
          {
            CDialog::DoDataExchange(pDX);
            DDX_Control(pDX, IDC_BUTTON1, m_button);
          } 
    NOTE: If you use Class Wizard to add a member variable in your dialog box class, it does this for you.


  3. Call CWnd::EnableWindow() to disable or enable the control when needed. For example, you can disable a button when the dialog box is initialized. For example:
    
          CMyDlg::OnInitDialog()
          {
           ...
           m_button.EnableWindow(FALSE);
           ...
          } 
    An alternative method is to use the CWnd::GetDlgItem() function to get a CWnd * to the control and then call EnableWindow(). For example:
    
          CMyDlg::OnInitDialog()
           {
            ...
            GetDlgItem(IDC_BUTTON)->EnableWindow(FALSE);
            ...
           } 


Additional query words: kbinf 1.00 1.50 2.00 2.10 2.50 2.51 2.52 3.00 3.10 4.00

Keywords : kbMFC KbUIDesign kbVC
Version : 1.00 1.50 1.51 1.52 | 1.00 2.00
Platform : NT WINDOWS
Issue type :


Last Reviewed: August 3, 1999
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