CheckedListBox.ItemCheck Event

Definition

Namespace:

System.Windows.Forms

Assembly:

System.Windows.Forms.dll

Occurs when the checked state of an item changes.

public:
 event System::Windows::Forms::ItemCheckEventHandler ^ ItemCheck;

public event System.Windows.Forms.ItemCheckEventHandler? ItemCheck;

member this.ItemCheck : System.Windows.Forms.ItemCheckEventHandler 

Public Custom Event ItemCheck As ItemCheckEventHandler 

Event Type

ItemCheckEventHandler

Examples

The following code example demonstrates the use of this member. In the example, an event handler reports on the occurrence of the ItemCheck event. This report helps you to learn when the event occurs and can assist you in debugging. To report on multiple events or on events that occur frequently, consider replacing MessageBox.Show with Console.WriteLine or appending the message to a multiline TextBox.

To run the example code, paste it into a project that contains an instance of type CheckedListBox named CheckedListBox1. Then ensure that the event handler is associated with the ItemCheck event.

private void CheckedListBox1_ItemCheck(Object sender, ItemCheckEventArgs e) {

System.Text.StringBuilder messageBoxCS = new System.Text.StringBuilder();
messageBoxCS.AppendFormat("{0} = {1}", "Index", e.Index );
messageBoxCS.AppendLine();
messageBoxCS.AppendFormat("{0} = {1}", "NewValue", e.NewValue );
messageBoxCS.AppendLine();
messageBoxCS.AppendFormat("{0} = {1}", "CurrentValue", e.CurrentValue );
messageBoxCS.AppendLine();
MessageBox.Show(messageBoxCS.ToString(), "ItemCheck Event" );
}

Private Sub CheckedListBox1_ItemCheck(sender as Object, e as ItemCheckEventArgs) _ 
     Handles CheckedListBox1.ItemCheck

    Dim messageBoxVB as New System.Text.StringBuilder()
    messageBoxVB.AppendFormat("{0} = {1}", "Index", e.Index)
    messageBoxVB.AppendLine()
    messageBoxVB.AppendFormat("{0} = {1}", "NewValue", e.NewValue)
    messageBoxVB.AppendLine()
    messageBoxVB.AppendFormat("{0} = {1}", "CurrentValue", e.CurrentValue)
    messageBoxVB.AppendLine()
    MessageBox.Show(messageBoxVB.ToString(),"ItemCheck Event")

End Sub

Remarks

The check state is not updated until after the ItemCheck event occurs.