/// <summary> /// Extends BeginInvoke so that when a state object is not needed, null does not need to be passed. /// <example> /// treevieweventhandler.BeginInvoke(sender, e, callback); /// </example> /// </summary> public static IAsyncResult BeginInvoke(this TreeViewEventHandler treevieweventhandler, Object sender, TreeViewEventArgs e, AsyncCallback callback) { if (treevieweventhandler == null) { throw new ArgumentNullException("treevieweventhandler"); } return(treevieweventhandler.BeginInvoke(sender, e, callback, null)); }