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:

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;
      ... 
```

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.

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