当一个类的实例的方法被赋给一个委托对象时,在上下文中不仅要维护这个方法,还要维护这个方法所在的实例。System.Delegate 类的Target属性指向的就是这个实例。举个例子:
class Program {
    static void Main(string[] args) {
        X x = new X();
        ProgressReporter p = x.InstanceProgress;
        p(1);
        Console.WriteLine(p.Target == x); // True
        Console.WriteLine(p.Method); // Void InstanceProgress(Int32)    
  }
    static void WriteProgressToConsole(int percentComplete) {
        Console.WriteLine(percentComplete+"%");
    }
    static void WriteProgressToFile(int percentComplete) {
        System.IO.File.AppendAllText("progress.txt", percentComplete + "%");
    }
}
 class X {
     public void InstanceProgress(int percentComplete) {
        // do something    
 }
}但对于静态方法,System.Delegate 类的Target属性是Null,所以将静态方法赋值给委托时性能更优。
来源:oschina
链接:https://my.oschina.net/u/4356296/blog/3236319
