What is the integer reference type in C#?

Question

I\'d like to have an integer variable which can be set to null and don\'t want to have to use the int? myVariable syntax. I tried using int and

Answer 1

Yes, it's the only way, as Int32/Int16/int is a primitive type (regardless of boxing/unboxing of these).

Answer 2

The <var>? syntax makes it nullable. If you dig a bit deeper, you'll see it's just a generic object that gets used.

If you want to do it like C++ you must use unsafe operations. Then, pointers like in C are available, but your code doesn't conform to CLR...

For using pure .NET without pointers, the ? is the way to go.

Answer 3

Nullable types are instances of the System.Nullable(T) struct.
Therefore int, int?, Nullable<int> are all value types, not reference types

Answer 4

You could use System.Nullable<int> if you hate ? so much.

Answer 5

You will have to use a nullable type, i.e:

Nullable<int> or int?

The purpose of nullable type is, to enable you to assign null to a value type.

From MSDN:

Nullable types address the scenario where you want to be able to have a primitive type with a null (or unknown) value. This is common in database scenarios, but is also useful in other situations.

In the past, there were several ways of doing this:

1. A boxed value type. This is not strongly-typed at compile-time, and involves doing a heap allocation for every type.
2. A class wrapper for the value type. This is strongly-typed, but still involves a heap allocation, and the you have to write the wrapper.
3. A struct wrapper that supports the concept of nullability. This is a good solution, but you have to write it yourself.

Answer 6

For info, int? / Nullable<T> is not a reference-type; it is simply a "nullable type", meaning: a struct (essentially and int and a bool flag) with special compiler rules (re null checks, operators, etc) and CLI rules (for boxing/unboxing). There is no "integer reference-type" in .NET, unless you count boxing:

int i = 123;
object o = i; // box

but this creates an unnecessary object and has lots of associated other issues.

For what you want, int? should be ideal. You could use the long-hand syntax (Nullable<int>) but IMO this is unnecessarily verbose, and I've seen it confuse people.