How to check that object implements interface

Question

Given this scenario

interface A {}

class B : A {}

A b = new B();

How can I check that object b is created from interface A?

Answer 1

Try to use is

if(b is A)
{
    // do something
}

is that what you want?

Answer 2

You could do test it like this:

var b = new B();

var asInterface = x as A;
if (asInterface == null) 
{
    //not of the interface A!
}