c# advanced lambda expression

From: Blog Garden - Halfway Alone

Original address: http://www.cnblogs.com/banluduxing/p/9007494.html 

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Before reading, make sure you have a basic understanding  of delegates .

 The first step of the prototype of lambda expression

In the delegate article, the bound methods are all named functions. In order to simplify writing, they can be replaced by anonymous functions.

public delegate void Write();
public delegate void Read(int x, string str);
public delegate int Get(int y);
static void Main(string[] args)
        {
            Write write = new Write(delegate() { 
                        Console.WriteLine("write"); });
            Read read = new Read(delegate (int x, string y){ 
                        Console.WriteLine("read"); });
            Get get = new Get(delegate (int x) { return 1; });
        }

The second step of the prototype of lambda expression

 Replace delegate() with ()=>, because the method and the delegate parameter signature are consistent, the parameter type can also be removed, the above can be simplified as

Write write = new Write(()=> { Console.WriteLine("write"); });
Read read = new Read(( x,y)=>{ Console.WriteLine("read"); });
Get get = new Get((x) =>{ return 1; });

The third step of the prototype of lambda expression

 Delegate initialization can directly bind the method, no need for new, the method body has only one line of code, and {} can be omitted, and if there is return, the return keyword can also be removed, which is simplified to

Write write = () => Console.WriteLine("write");
Read read = (x, y) => Console.WriteLine("read");
Get get = (x) => 1;

Just remember that  the essence of a lambda expression is a method, then the lambda expression becomes less complicated