.Net学习笔记——委托代理Delegate2(组合委托)-- 组合委托 委托对象的一个有用属性是,它们可以“+”运算符来组合。组合的委托可调用组成它的那两个委托。只有相同类型的委托才可以组合。 “-”运算符可用来从组合的委托移除组件委托。 // compose.cs using System; delegatevoid MyDelegate(string s); class MyClass { publicstaticvoid Hello(string s) { Console.WriteLine(" Hello, {0}!", s); } publicstaticvoid Goodbye(string s) { Console.WriteLine(" Goodbye, {0}!", s); } publicstaticvoid Main() { MyDelegate a, b, c, d; // Create the delegate object a that references // the method Hello: a =new MyDelegate(Hello); // Create the delegate object b that references // the method Goodbye: b =new MyDelegate(Goodbye); // The two delegates, a and b, are composed to form c: c = a + b; // Remove a from the composed delegate, leaving d, // which calls only the method Goodbye: d = c - a; Console.WriteLine("Invoking delegate a:"); a("A"); Console.WriteLine("Invoking delegate b:"); b("B"); Console.WriteLine("Invoking delegate c:"); c("C"); Console.WriteLine("Invoking delegate d:"); d("D"); } } 输出Invoking delegate a: Hello, A! Invoking delegate b: Goodbye, B! Invoking delegate c: Hello, C! Goodbye, C! Invoking delegate d: Goodbye, D!