C＃泛型方法重载

Question

I have problem with C# generics. I need do something like this, in PCL.

class Factory<T> : IFactory<T>
{
    T Create()
    {
          throw new NotSupportedException();
    }
}

class Factory : IFactory<MyClass>
{
    MyClass Create()
    {
         return new MyClass();
    }
}

//In some method ....
IFactory<MyClass> factory = new Factory<MyClass>();
MyClass variable = factory.Create(); //This throw NotSupportedException

I know this is bulshit, but I try many solutions and no of them work :-(

Answer 1

You're creating an instance of Factory<T> , not Factory . Factory<T>.Create throws an exception, so the behavior you're seeing is normal.

You should use Factory instead of Factory<T> .

Another option is to add a new constraint on T in Factory<T> :

class Factory<T> : IFactory<T> where T : new()
{
    public T Create()
    {
          return new T()
    }
}

Answer 2

The Factory<T> class doesn't serve any purpose in your example, since your Factory is inheriting directly from IFactory<T> . If you're going to do that, you can just delete the first class, and do this:

IFactory<MyClass> factory = new Factory();
MyClass variable = factory.Create();

The reason you're getting an exception is because you're creating an instance of Factory<T> , and that is defined to throw an exception when .Create() is called on it.