在c＃中创建实例时覆盖抽象方法

Question

In java, we can override or implement abstract methods upon instance creation as follows:

AbstractClass test =new AbstractClass() 
{
    public void AbstractMethod(string i) {

    }
    public void AbstractMethod2(string i) {

    }
};

Is this possible in C#? if Yes, what's the equivalent code

Thanks

Answer 1

This Java feature is called "anonymous class" , not "an override of method on instance creation". There is no identical feature in C#.

C# took a different route - instead of providing convenience syntax for creation of subclasses, it expanded upon its delegate features, providing anonymous delegates and lambdas . Lambdas let you plug in pieces of code.

Answer 2

You can achieve something very similar through clever use of lambdas:

public class BaseClass {

    public BaseClass(Action<string> abs1 = null, Action<string> abs2 = null){
       AbstractMethod1 = abs1 ?? s=>{};
       AbstractMethod2 = abs2 ?? s=>{};
    }

    public Action<string> AbstractMethod1 {get; private set;}
    public Action<string> AbstractMethod2 {get; private set;}
}

So you could use this definition like so:

new BaseClass( s=> Console.WriteLine(s), s=> Console.WriteLine(s));

You could also define all the methods as part of an interface and then construct a class with a concrete implementation of the interface (proxying the calls to the concrete implementation) -- I would call that the "Strategy" Pattern. But that's just a variation of this theme.

Answer 3

Don't know Java , but this "smells" like Anonymous Types in C# .

For example, you can write something like:

 var myNewType = new { 
                       Name = "Charles", 
                       Surname="Dickens", 
                       Age = 55 
                      };