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ListBox.SelectedIndexChanged Event

Occurs when the SelectedIndex property has changed.

Namespace: System.Windows.Forms
Assembly: System.Windows.Forms (in system.windows.forms.dll)

public event EventHandler SelectedIndexChanged
/** @event */
public void add_SelectedIndexChanged (EventHandler value)

/** @event */
public void remove_SelectedIndexChanged (EventHandler value)

In JScript, you can handle the events defined by a class, but you cannot define your own.
Not applicable.

You can create an event handler for this event to determine when the selected index in the ListBox has been changed. This can be useful when you need to display information in other controls based on the current selection in the ListBox. You can use the event handler for this event to load the information in the other controls.

For more information about handling events, see Consuming Events.

The following code example demonstrates how to use the SelectedIndexChanged event to search for and select an item in a different ListBox control. The example uses the SelectedIndexChanged event to determine when the selected item in the ListBox is changed. The example code then reads the text of the item using the SelectedItem property and calls the FindString method on a different ListBox using the text returned by SelectedItem in the first ListBox. If an item is found in the other ListBox, the item is selected. This example requires that two ListBox controls, named listBox1 and listBox2, have been added to a form and that both ListBox controls contain items that are identical. The example also requires that the event-handling method defined in the example is connected to the SelectedIndexChanged event of listBox1.

private void listBox1_SelectedIndexChanged(object sender, System.EventArgs e)
{
   // Get the currently selected item in the ListBox.
   string curItem = listBox1.SelectedItem.ToString();

   // Find the string in ListBox2.
   int index = listBox2.FindString(curItem);
   // If the item was not found in ListBox 2 display a message box, otherwise select it in ListBox2.
   if(index == -1)
      MessageBox.Show("Item is not available in ListBox2");
   else
      listBox2.SetSelected(index,true);
}

private void listBox1_SelectedIndexChanged(Object sender, 
    System.EventArgs e)
{
    // Get the currently selected item in the ListBox.
    String curItem = listBox1.get_SelectedItem().ToString();
    // Find the string in ListBox2.
    int index = listBox2.FindString(curItem);
    // If the item was not found in ListBox 2 display a message box, 
    // otherwise select it in ListBox2.
    if (index == -1) {
        MessageBox.Show("Item is not available in ListBox2");
    }
    else {
        listBox2.SetSelected(index, true);
    }
} //listBox1_SelectedIndexChanged 

Windows 98, Windows Server 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.

.NET Framework

Supported in: 3.0, 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 2.0, 1.0

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