7. Simple application of object-oriented and WinForm (entrustment)

Commissioned

1. Concept:

A delegate can be thought of as a "container" of a function, and it can be used as a function after "loading" a specific function. A delegate variable can be thought of as a type-safe function pointer that can receive only the address of a function that meets its requirements.

2, definition method: Delegate keyword. Cases:

     Public Delegate int Mydele (intint b);

3, using the delegate call function

1) Define a class first and write a few methods:

    class Class1    {        publicint jiafa (intint  b)        {            return A + b;        }          Public int JIANFA (intint  b)        {            return A- b;        }
    }

2) Call the function through the delegate:

//Define a variable of an existing delegate type New //Assign values to the above variables Console.WriteLine (M (1,2));  The result is 3new Class1 (). JIANFA; Console.WriteLine (M (1,2)); //result is-1

4. Note: A variable of a delegate type can refer to any function that satisfies its requirements.

5, the extension of the delegation:

1) Special delegate generic set, anonymous delegate

func<stringstringnew Class1 (). returnstring; // input string, output string Console.WriteLine (MyFunc (" Zhang San "));

2) Direct Write method

func<stringstringdelegate(string  s) {      return]  world! " ;            }; Console.WriteLine (Newfunc (" John Doe "));

3) Lambda method simple version 1, replace delegate with s=> (string s)

func<stringstring> newfunc1 = s=> {          return'world! "

4) lambda method simple version 2, two parameters

func<stringstring,string> Newfunc2 = (s1,s2) + =         { return " world! "+s2;             

5) Lambda method simple version 2, remove curly braces, direct write method

func<stringstring,string> newfunc3 = (S1, s2) =>s1+"world! "+s2;             
Console.ReadLine ();

7. Simple application of object-oriented and WinForm (entrustment)