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ListBox.SetSelected Method

Selects or clears the selection for the specified item in a ListBox.

Namespace:  System.Windows.Forms
Assembly:  System.Windows.Forms (in System.Windows.Forms.dll)

public void SetSelected(
	int index,
	bool value


Type: System.Int32

The zero-based index of the item in a ListBox to select or clear the selection for.

Type: System.Boolean

true to select the specified item; otherwise, false.


The specified index was outside the range of valid values.


The SelectionMode property was set to None.

You can use this property to set the selection of items in a multiple-selection ListBox. To select an item in a single-selection ListBox, use the SelectedIndex property.

The following code 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 requires that the code is located in and called from a Form.

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. 
   // 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.
   // 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.

   // 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.
   // Display the index of the first selected item in the ListBox.

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

.NET Framework

Supported in: 3.5, 3.0, 2.0, 1.1, 1.0