Is creating a C# generic method that accepts (nullable) value type and reference type possible?

Question

I want to create a simple method that accepts both value type and reference type parameters, i.e. int is value, and string is reference.

So this i

Answer 1

Your problem is that you want generic type constraints that are conflicting with each other:

• Nullable<T> works with value types only
• Reference types are not value types

So you will need to have two overloads for your code to work:

public static bool areBothNotNull<T>(T? p1, T? p2) where T : struct
{            
    return (p1.HasValue && p2.HasValue);
}

public static bool areBothNotNull<T>(T p1, T p2)
{
    return (p1 != null && p2 != null);
}

Still, the following line will never compile:

var r3 = areBothNotNull<string>(3, 4);

There is a conflict here, where the generic type argument states that the parameters are of type string, but the code tries to pass ints instead.