CODEWITHSUNDEEP
c#radix
Jason
Jason

Reputation: 504

About base in C#

namespace contest
{
    class Program
    {
        static void Main(string[] args)
        {
            B b = new B();
        }
    }

    class A {
        public A() {
            k();
        }
        private void k() {
            Console.WriteLine(base.GetType().Name);
        }        
    }

    class B : A {

    }
}

Can someone tell me why it outputs "B" instead of "Object", doesn't base.GetType() get A's parent object therefore the root Object?

Thanks a lot

Upvotes: 0

Views: 160

Answers (3)

Mike Zboray
Mike Zboray

Reputation: 40818

GetType is defined on System.Object and is not virtual. It provides the runtime type of the object from the metadata. Therefore, it doesn't matter where you call it (in a constructor or virtual method) or if you use base or this you are always calling the same method. You will always get the runtime type, except in the case of Nullable types where you will get the underlying type. My guess is that this is due the special boxing behavior of nullables. See this on identifying nullable types.

Upvotes: 0

fenix2222
fenix2222

Reputation: 4730

B implements/inherits from A, when you initialise B b = new B() it will just use guts of a and therefore return type of the B. Try using A b = new B(); this should return A. You need to override method and also define A as abstract.

Upvotes: 0

zerkms
zerkms

Reputation: 254916

That happens because 

base.GetType()

means "call the GetType() method of parent class", though you haven't overriden it. Thus base.GetType() as well as this.GetType() would always return class B

Upvotes: 3

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