Avoid generic arguments

Question

I have the following extension method which asserts that a property (Id) contains a specified attribute (TV):

public static void ShouldHave<T, TV, TT>(this T obj, Expression<Func<T, TT>> exp) {...}

The method can be called like this:

MyDto myDto = new MyDto();
myDto.ShouldHave<MyDto, RequiredAttribute, int>(x => x.Id);

Compiles just fine. I was wondering if it is possible to remove T and TT from the method signature. T because ShouldHave is called on T why it shouldn't be necessary to specify it explicitly. And TT is the type of the property referenced in the expression (x.Id).

Answer 1

The following compiles:

public static void ShouldHave<T, TT>(this T obj, Expression<Func<T, TT>> exp)
{...}

MyDto myDto = new MyDto();
myDto.ShouldHave(x => x.Id);

This omits the TV type argument, which is the reason for your need to explicitly specify the generic arguments at the call site. If you need this argument then you’re out of luck.