using System; using System.ComponentModel; using System.Windows; namespace CustomControls { [DesignTimeVisible(false)] public partial class ToolStripSplitButton : DropDownButtonBase { public event EventHandler SplitButtonClick; public override void OnApplyTemplate() { base.OnApplyTemplate(); var split = Template.FindName("split", this) as UIElement; split.MouseDown += (s, e) => e.Handled = true; split.MouseLeftButtonUp += (s, e) => SplitButtonClick?.Invoke(this, e); } public ToolStripSplitButton() { InitializeComponent(); } } }