The problem is that both string
and object
are nullable, so null
could refer to either overload of the method. You have to cast the null value—as stupid as that sounds—to say explicitely which overload you want to call.
method("string", (string) null);
method("string", (object) null);
This is basically the same as if you defined a variable of either type and passed that then:
string param1 = null;
object param2 = null;
method("string", param1); // will call the string overload
method("string", param2); // will call the object overload
Both param1
and param2
have the same value, null
, but the variables are of different types which is why the compiler is able to tell exactly which overload it needs to use. The solution above with the explicit cast is just the same; it annotates a type to the null
value which is then used to infer the correct overload—just without having to declare a variable.
与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…