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C# 匿名函数

2011-10-18 09:42  Eric.Hu  阅读(767)  评论(0编辑  收藏  举报

委托是一种包装方法调用的类型。就像类型一样,可以在方法之间传递委托实例,并且可以像方法一样调用委托实例。匿名函数是一个“内联”语句或表达式,可在需要委托类型的任何地方使用。可以使用匿名函数来初始化命名委托,或传递命名委托(而不是命名委托类型)作为方法参数。

Lambda 表达式可以绑定到表达式目录树,也可以绑定到委托。

示例:

class Test
{
delegate void TestDelegate(string s);
static void M(string s)
{
Console.WriteLine(s);
}

static void Main(string[] args)
{
// Original delegate syntax required
// initialization with a named method.
TestDelegate testdelA = new TestDelegate(M);

// C# 2.0: A delegate can be initialized with
// inline code, called an "anonymous method." This
// method takes a string as an input parameter.
TestDelegate testDelB = delegate(string s) { Console.WriteLine(s); };

// C# 3.0. A delegate can be initialized with
// a lambda expression. The lambda also takes a string
// as an input parameter (x). The type of x is inferred by the compiler.
TestDelegate testDelC = (x) => { Console.WriteLine(x); };

// Invoke the delegates.
testdelA("Hello. My name is M and I write lines.");
testDelB("That's nothing. I'm anonymous and ");
testDelC("I'm a famous author.");

// Keep console window open in debug mode.
Console.WriteLine("Press any key to exit.");
Console.ReadKey();
}
}
/* Output:
Hello. My name is M and I write lines.
That's nothing. I'm anonymous and
I'm a famous author.
Press any key to exit.
*/