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 #.

1 // function definition. The parameter is string and the return value is string2 Func <string, string> myFunc = delegate (string msg) 3 {4 return "Msg:" + msg; 5 };

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

1  //Lambda2  Func<string, string> myFuncSame = msg => "Msg:" + msg;

After defining a function, you can call it:

1 // function call 2 string message = myFuncSame ("Hello world ");

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

1 public static Func <int, int> Func () 2 {3 var myVar = 1; 4 Func <int, int> inc = delegate (int var1) 5 {6 // myVar can record the status (value) after the last call. 7 myVar = myVar + 1; 8 return var1 + myVar; 9}; 10 return inc; 11}

C # Closure is called as follows:

1 static void CsharpClosures()2 {3     var inc = Func();4     Console.WriteLine(inc(5));//75     Console.WriteLine(inc(6));//96 }

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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Source: http://www.cnblogs.com/isaboy/
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