委托是一个引用方法的对象,或者可以说它是一个引用类型变量,可以保存对方法的引用。 C#中的委托类似于C / C++中的函数指针。它提供了一种方法,该方法告诉事件触发时将调用哪个方法。
例子:
// C# program to illustrate Delegates
using System;
class GFG {
// Declaring the delegates
public delegate void AddVal(int x, int y);
public void SMeth(int x, int y)
{
Console.WriteLine("[190 + 70] = [{0}]", x + y);
}
// Main Method
public static void Main(String[] args)
{
// Creating the object of GFG class
GFG o = new GFG();
// Creating object of delegate
AddVal obj = new AddVal(o.SMeth);
// Pass the values to the method
// Using delegate object
obj(190, 70);
}
}
输出:
[190 + 70] = [260]
像类一样, Interface可以将方法,属性,事件和索引器作为其成员。但是接口将仅包含成员的声明。接口成员的实现将由隐式或显式实现接口的类给出。
例子:
// C# program to illustrate the
// concept of interface
using System;
// A simple interface
interface inter {
// method having only declaration
// not definition
void display();
}
// A class that implements the interface
class Geeks : inter {
// providing the body part of function
public void display()
{
Console.WriteLine("Welcome to GeeksforGeeks..!");
}
// Main Method
public static void Main(String[] args)
{
// Creating object
Geeks o = new Geeks();
// calling method
o.display();
}
}
输出:
Welcome to GeeksforGeeks..!
以下是C#中的“委托”和“接口”之间的一些区别:
Delegate | Interface |
---|---|
It could be a method only. | It contains both methods and properties. |
It can be applied to one method at a time. | If a class implements an interface, then it will implement all the methods related to that interface. |
If a delegate available in your scope you can use it. | Interface is used when your class implements that interface, otherwise not. |
Delegates can me implemented any number of times. | Interface can be implemented only one time. |
It is used to handling events. | It is not used for handling events. |
It can access anonymous methods. | It can not access anonymous methods. |
When you access the method using delegates you do not require any access to the object of the class where the method is defined. | When you access the method you need the object of the class which implemented an interface. |
It does not support inheritance. | It supports inheritance. |
It can wrap static methods and sealed class methods | It does not wrap static methods and sealed class methods.. |
It created at run time. | It created at compile time. |
It can implement any method that provides the same signature with the given delegate. | If the method of interface implemented, then the same name and signature method override. |
It can wrap any method whose signature is similar to the delegate and does not consider which from class it belongs. | A class can implement any number of interfaces, but can only override those methods which belongs to the interfaces. |