WPF:求教怎么注销一个控件下的指定事件

WPF:求教如何注销一个控件上的指定事件？
比如如何注销一个按钮btn上的Click事件？

[解决办法]

C# code

 static void Main(string[] args)        {            System.Windows.Forms.Button btn = new System.Windows.Forms.Button();            btn.Click += new EventHandler(btn_Click);            btn.Click += new EventHandler(btn_Click2);            btn.Click += new EventHandler(btn_Click3);            PropertyInfo pi = btn.GetType().GetProperty("Events", BindingFlags.Instance | BindingFlags.NonPublic);            EventHandlerList ehl = (EventHandlerList)pi.GetValue(btn, null);            FieldInfo fieldInfo = (typeof(System.Windows.Forms.Control)).GetField("EventClick", BindingFlags.Static | BindingFlags.NonPublic);            Delegate d = ehl[fieldInfo.GetValue(null)];            foreach (Delegate del in d.GetInvocationList())                Console.WriteLine(del.Method.Name);        }        static void btn_Click(object sender, EventArgs e)        {            Console.WriteLine("Click1");        }        static void btn_Click2(object sender, EventArgs e)        {            Console.WriteLine("Click2");        }        static void btn_Click3(object sender, EventArgs e)        {            Console.WriteLine("Click3");        }