MFC - List Box


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A list box displays a list of items, such as filenames, that the user can view and select. A List box is represented by CListBox class. In a single-selection list box, the user can select only one item. In a multiple-selection list box, a range of items can be selected. When the user selects an item, it is highlighted and the list box sends a notification message to the parent window.

Here are some mapping entries for Listbox −

Message Map entry Description
LBN_DBLCLK ON_LBN_DBLCLK( <id>, <memberFxn> ) The framework calls this member function when list item is double clicked.
LBN_KILLFOCUS ON_LBN_KILLFOCUS( <id>, <memberFxn> ) The framework calls this member function immediately before losing the input focus.
LBN_SELCHANGE ON_LBN_SELCHANGE( <id>, <memberFxn> ) The framework calls this member function when selection is changed.
LBN_SETFOCUS ON_LBN_SETFOCUS( <id>, <memberFxn> ) The framework calls this member function after gaining the input focus.

Let us look into a simple example of List box by creating a new MFC dialog based application.

Step 1 − Once the project is created, you will see the TODO line which is the Caption of Text Control. Remove the Caption and set its ID to IDC_STATIC_TXT.

Step 2 − Drag List Box from the Toolbox.

Listbox1

Step 3 − Add the control variable for the Text control.

Listbox2

Step 4 − Add the Value variable for the Text control.

Listbox3

Step 5 − Add the control variable for the List Box control.

Listbox4

Step 6 − Add the event handler for the List Box control.

Listbox5

Step 7 − Select the LBN_SELCHANGE from the message type and enter name for the event handler.

Step 8 − Add one function, which will load the list box.

void CMFCListBoxDlg::LoadListBox() {
   CString str = _T("");
   for (int i = 0; i<10; i++) {

      str.Format(_T("Item %d"), i);
      m_listBox.AddString(str);
   }
}

Step 9 − Call the function from CMFCListBoxDlg::OnInitDialog() as shown in the following code.

BOOL CMFCListBoxDlg::OnInitDialog() {
   CDialogEx::OnInitDialog();

   // Set the icon for this dialog. The framework does this automatically
   // when the application's main window is not a dialog
   SetIcon(m_hIcon, TRUE);       // Set big icon
   SetIcon(m_hIcon, FALSE);      // Set small icon

   // TODO: Add extra initialization here
   LoadListBox();
   return TRUE; // return TRUE unless you set the focus to a control
}

Step 10 − Here is the event handler implementation. This will display the current selected item from the List Box.

void CMFCListBoxDlg::OnLbnSelchangeList1() {
   // TODO: Add your control notification handler code here
   m_listBox.GetText(m_listBox.GetCurSel(),m_strItemSelected);
   UpdateData(FALSE);
}

Step 11 − When the above code is compiled and executed, you will see the following output.

Listbox6

Step 12 − When you select any item, it will be displayed on the Text Control.

mfc_windows_controls.htm
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