Is boxing involved when calling ToString for integer types?

Question

Very simple question: ``` int a = 5; string str = a.ToString(); ``` Since `ToString` is a virtual method of System.Object, does it mean that everytime I call this method for integer types, a boxing occurs?

Accepted Answer

You've already got answers telling you that when `ToString()` is overridden for a value type, there will be no boxing when you call it, but it's nice to have some way of actually seeing that.

Take the type `int?` (`Nullable<int>`). This is a useful type because it is a value type, yet boxing may produce a null reference, and instance methods cannot be called through a null reference. It does have an overridden `ToString()` method. It does not have (and cannot have) an overridden `GetType()` method.

```
int? i = null;
var s = i.ToString(); // okay: initialises s to ""
var t = i.GetType(); // not okay: throws NullReferenceException
```

This shows that there is no boxing in the call `i.ToString()`, but there is boxing in the call `i.GetType()`.

Is boxing involved when calling ToString for integer types?

Solution

Problem