Why are C# calls different for overloaded methods for different values of the same type?

Question

Hello all,

I have one doubt concerning c# method overloading and call resolution.

Let's suppose I have the following C# code:

enum MyEnum { Value1, Value2 }

public void test() {
    method(0); // this calls method(MyEnum)
    method(1); // this calls method(object)
}

public void method(object o) {
}

public void method(MyEnum e) {
}

Note that I know how to make it work but I would like to know why for one value of int (0) it calls one method and for another (1) it calls another. It sounds awkward since both values have the same type (int) but they are "linked" for different methods.

Ps.: This is my first question here, i'm sorry if I made something wrong. =P

Answer 1

Literal 0 is implicitly convertible to any enum type, which is a closer match than object. Spec.

See, for example, these blog posts.

Answer 2

I'm pretty sure to call

public void method(MyEnum e) {
}

properly you need to pass in MyEnum.Value1 or MyEnum.Value2. Enum != int type, hence why you have to cast the int to your enum type. So (MyEnum)1 or (MyEnum)0 would work properly.

In your case, 0 was implicitly cast to your enum type.

Answer 3

This has already been answered here

Answer 4

Why does C# allow implicit conversion of literal zero to any enum? is a good reference that has a great answer by JaredPar in it.