How to Create C # Closure ?,

How to Create C # Closure ?,

An important concept in JavaScript is closure. Closure has a large number of applications in JavaScript, but do you know? C # You can also create Closure. The following describes how to create a magic closure in C.

Before that, we must first know how to define functions in C #.

// Function definition. The parameter is string and the return value is string Func <string, string> myFunc = delegate (string msg) {return "Msg:" + msg ;};

Lambda expressions can simplify the above Code, but the effect is the same:

  //Lambda Func<string, string> myFuncSame = msg => "Msg:" + msg;

After defining a function, you can call it:

// Function call string message = myFuncSame ("Hello world ");

Defines a nested function with external variables (relative to embedded functions). External functions return nested functions:

Public static Func <int, int> Func () {var myVar = 1; Func <int, int> inc = delegate (int var1) {// myVar can record the status (value) after the last call. myVar = myVar + 1; return var1 + myVar ;}; return inc ;}

C # Closure is called as follows:

static void CsharpClosures() {     var inc = Func();     Console.WriteLine(inc(5));//7     Console.WriteLine(inc(6));//9 }

When inc (6) is called for the second time, the variable myVar in the function does not reinitialize (var myVar = 1) as it does when the function is called for the first time, but retains the value of the first operation, 2. Therefore, the result returned by inc (6) is (2 + 1 + 6) = 9.

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