AsyncWorker - A Typesafe BackgroundWorker (and about Threading in General)

using System;
using System.Windows.Forms;
using System.ComponentModel;

namespace AsyncWorkerCs {
   public partial class uclExceptions : UserControl {

      private Action<string> _ThrowEx = delegate(string text) { throw new Exception(text); }; 

      public uclExceptions() {         InitializeComponent();      }

      private void btBackgroundworker_Click(object sender, EventArgs e) {
         backgroundWorker1.RunWorkerAsync();
      }

      private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e) {
         _ThrowEx("thrown by  backgroundWorker1"); 
      }

      private void btWithoutEndInvoke_Click(object sender, EventArgs e) {
         _ThrowEx.BeginInvoke("thrown without EndInvoke", null, null);
      }

      private void btWithEndInvoke_Click(object sender, EventArgs e) {
         _ThrowEx.BeginInvoke("thrown with EndInvoke", _ThrowEx.EndInvoke, null);
      }

      private void btAsyncworker_Click(object sender, EventArgs e) {
         _ThrowEx.RunAsync("thrown by Asyncworker"); 
      }

      private void btSynchron_Click(object sender, EventArgs e) {
         _ThrowEx("thrown in main-thread"); 
      }
   }
}