Object-oriented (delegate)

Commissioned

parameterization of the method It is also called an agent to pass the method as a parameter, and the event is a delegate.

Defined at the outermost of the class

Key Words: Delegate

Function Signature: Signature and function remain consistent

When defining a delegate, you define it according to the function.

public delegate int first (int a,int b);

The return type of the method pointed to requires the parameters to be consistent!

2 , defining a delegate variable, pointing to a method

A delegate cannot be instantiated because it is not a class;

First f = new Jiafa (). Jiafa; New delegate variable, point to method, note!! method does not need parentheses!!

The second time you can use +=

public int Jiafa (int a,int b)

{

return a+b;

}

Call:

f (5,3);

Can be understood as a pointer to a function, which function the delegate points to, which function is represented by the delegate

Allows functions to be passed as arguments

Cases:

Defining delegates

public delegate void Suibian (string s);

Class Program

{

static void Main (string[] args)

{

Test T1 = new test ();

Test t2 = new Test ();

DBDA db = Dbda. Duixiang ();

Db.host = "localhost";

Dbda db1 = Dbda. Duixiang ();

Commissioned

Parameterization of the method

Suibian s = China;

s + = America; + = is the binding method = minus a method

Event

Events are a special kind of delegate

Calling a speech method

Speak (s);

Console.WriteLine ();

Console.ReadLine ();

}

Methods of speech function

static void Speak (Suibian yu)

{

Yu ("Zhang San");

if (n = = 0)

//{

America ();

//}

else if (n = = 1)

//{

China ();

//}

else if (n = = 2)

//{

Hanyu ();

//}

}

Voice Pack

public static void America (string s)

{

Console.WriteLine (s+ "Hello");

}

static void China (string s)

{

Console.WriteLine (s+ "Hello");

}

static void Hanyu (string s)

{

Console.WriteLine (s+ "Bjdkaj");

}

}

Object-oriented (delegate)