Export (0) Print
Expand All

ListBox Constructor

Initializes a new instance of the ListBox class.

[Visual Basic]
Public Sub New()
[C#]
public ListBox();
[C++]
public: ListBox();
[JScript]
public function ListBox();

Example

The following example demonstrates how to create a ListBox control that displays multiple items in columns and can have more than one item selected in the control's list. The code for the example adds 50 items to the ListBox using the Add method of the ListBox.ObjectCollection class and then selects three items from the list using the SetSelected method. The code then displays values from the ListBox.SelectedObjectCollection collection (through the SelectedItems property) and the ListBox.SelectedIndexCollection (through the SelectedIndices property). This example assumes that the code is located in and called from a Form.

[Visual Basic] 
Private Sub button1_Click(sender As Object, e As System.EventArgs)
    ' Create an instance of the ListBox.
    Dim listBox1 As New ListBox()
    ' Set the size and location of the ListBox.
    listBox1.Size = New System.Drawing.Size(200, 100)
    listBox1.Location = New System.Drawing.Point(10, 10)
    ' Add the ListBox to the form.
    Me.Controls.Add(listBox1)
    ' Set the ListBox to display items in multiple columns.
    listBox1.MultiColumn = True
    ' Set the selection mode to multiple and extended.
    listBox1.SelectionMode = SelectionMode.MultiExtended
    
    ' Shutdown the painting of the ListBox as items are added.
    listBox1.BeginUpdate()
    ' Loop through and add 50 items to the ListBox.
    Dim x As Integer
    For x = 1 To 50
        listBox1.Items.Add("Item " & x.ToString())
    Next x
    ' Allow the ListBox to repaint and display the new items.
    listBox1.EndUpdate()
    
    ' Select three items from the ListBox.
    listBox1.SetSelected(1, True)
    listBox1.SetSelected(3, True)
    listBox1.SetSelected(5, True)
       
    ' Display the second selected item in the ListBox to the console.
    System.Diagnostics.Debug.WriteLine(listBox1.SelectedItems(1).ToString())
    ' Display the index of the first selected item in the ListBox.
    System.Diagnostics.Debug.WriteLine(listBox1.SelectedIndices(0).ToString())
End Sub


[C#] 
private void button1_Click(object sender, System.EventArgs e)
{
   // Create an instance of the ListBox.
   ListBox listBox1 = new ListBox();
   // Set the size and location of the ListBox.
   listBox1.Size = new System.Drawing.Size(200, 100);
   listBox1.Location = new System.Drawing.Point(10,10);
   // Add the ListBox to the form.
   this.Controls.Add(listBox1);
   // Set the ListBox to display items in multiple columns.
   listBox1.MultiColumn = true;
   // Set the selection mode to multiple and extended.
   listBox1.SelectionMode = SelectionMode.MultiExtended;
 
   // Shutdown the painting of the ListBox as items are added.
   listBox1.BeginUpdate();
   // Loop through and add 50 items to the ListBox.
   for (int x = 1; x <= 50; x++)
   {
      listBox1.Items.Add("Item " + x.ToString());
   }
   // Allow the ListBox to repaint and display the new items.
   listBox1.EndUpdate();
      
   // Select three items from the ListBox.
   listBox1.SetSelected(1, true);
   listBox1.SetSelected(3, true);
   listBox1.SetSelected(5, true);

   // Display the second selected item in the ListBox to the console.
   System.Diagnostics.Debug.WriteLine(listBox1.SelectedItems[1].ToString());
   // Display the index of the first selected item in the ListBox.
   System.Diagnostics.Debug.WriteLine(listBox1.SelectedIndices[0].ToString());             
}


[C++] 
private:
void button1_Click(Object* /*sender*/, System::EventArgs* /*e*/)
{
   // Create an instance of the ListBox.
   ListBox* listBox1 = new ListBox();
   // Set the size and location of the ListBox.
   listBox1->Size = System::Drawing::Size(200, 100);
   listBox1->Location = System::Drawing::Point(10,10);
   // Add the ListBox to the form.
   this->Controls->Add(listBox1);
   // Set the ListBox to display items in multiple columns.
   listBox1->MultiColumn = true;
   // Set the selection mode to multiple and extended.
   listBox1->SelectionMode = SelectionMode::MultiExtended;
 
   // Shutdown the painting of the ListBox as items are added.
   listBox1->BeginUpdate();
   // Loop through and add 50 items to the ListBox.
   for (int x = 1; x <= 50; x++)
   {
      listBox1->Items->Add(String::Format( S"Item {0}", __box(x)));
   }
   // Allow the ListBox to repaint and display the new items.
   listBox1->EndUpdate();
      
   // Select three items from the ListBox.
   listBox1->SetSelected(1, true);
   listBox1->SetSelected(3, true);
   listBox1->SetSelected(5, true);

   // Display the second selected item in the ListBox to the console.
   System::Diagnostics::Debug::WriteLine(listBox1->SelectedItems->Item[1]);
   // Display the index of the first selected item in the ListBox.
   System::Diagnostics::Debug::WriteLine( __box(listBox1->SelectedIndices->Item[0]));             
}


[JScript] 
private function button1_Click(sender : Object, e : System.EventArgs)
{
   // Create an instance of the ListBox.
   var listBox1 : ListBox = new ListBox();
   // Set the size and location of the ListBox.
   listBox1.Size = new System.Drawing.Size(200, 100);
   listBox1.Location = new System.Drawing.Point(10,10);
   // Add the ListBox to the form.
   this.Controls.Add(listBox1);
   // Set the ListBox to display items in multiple columns.
   listBox1.MultiColumn = true;
   // Set the selection mode to multiple and extended.
   listBox1.SelectionMode = SelectionMode.MultiExtended;
 
   // Shutdown the painting of the ListBox as items are added.
   listBox1.BeginUpdate();
   // Loop through and add 50 items to the ListBox.
   for (var x : int = 1; x <= 50; x++)
   {
      listBox1.Items.Add("Item " + x.ToString());
   }
   // Allow the ListBox to repaint and display the new items.
   listBox1.EndUpdate();
      
   // Select three items from the ListBox.
   listBox1.SetSelected(1, true);
   listBox1.SetSelected(3, true);
   listBox1.SetSelected(5, true);

   // Display the second selected item in the ListBox to the console.
   System.Diagnostics.Debug.WriteLine(listBox1.SelectedItems[1].ToString());
   // Display the index of the first selected item in the ListBox.
   System.Diagnostics.Debug.WriteLine(listBox1.SelectedIndices[0].ToString());             
}

Requirements

Platforms: Windows 98, Windows NT 4.0, Windows Millennium Edition, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 family, .NET Compact Framework

See Also

ListBox Class | ListBox Members | System.Windows.Forms Namespace

Show:
© 2014 Microsoft