Possible to overload null-coalescing operator?

Question

Is it possible to overload the null-coalescing operator for a class in C#?

Say for example I want to return a default value if an instance is null and return the instance if it's not. The code would look like something like this:

   return instance ?? new MyClass("Default");  

But what if I would like to use the null-coalescing operator to also check if the MyClass.MyValue is set?

Answer 1

Good question! It's not listed one way or another in the list of overloadable and non-overloadable operators and nothing's mentioned on the operator's page.

So I tried the following:

public class TestClass
{
    public static TestClass operator ??(TestClass  test1, TestClass test2)
    {
        return test1;
    }
}

and I get the error "Overloadable binary operator expected". So I'd say the answer is, as of .NET 3.5, a no.