Operator '??' cannot be applied to operands of type 'T' and 'T'

Question

I have the following generic method, but VS gives me a compile error on that. (Operator \'??\' cannot be applied to operands of type \'T\' and \'T\')

public stat         


        

Answer 1

You should add class constraint:

public static T Method(T model) where T : class, new()
{
    var m = model ?? new T();

    return m;
}

And you should return m too!

Note: As @KristofDegrave mentioned in his comment, the reason that we have to add class constraint is because T can be a value type, like int and since ?? operator (null-coalescing) check on types that can be null, so we have to add class constraint to exclude value types.

Edit: Alvin Wong's answer covered the case for nullable types too; which are structs actually, but can be operands of ?? operator. Just be aware that Method would return null without Alvin's overloaded version, for nullable types.