How to set null value to int in c#?

Question

int value=0;  if (value == 0) {     value = null; } 

How can I set value to null above?

Any help will be appreciated.

Answer 1

In .Net, you cannot assign a null value to an int or any other struct. Instead, use a Nullable<int>, or int? for short:

int? value = 0;  if (value == 0) {     value = null; } 

Further Reading

• Nullable Types (C# Programming Guide)

Answer 2

Additionally, you cannot use "null" as a value in a conditional assignment. e.g...

bool testvalue = false; int? myint = (testvalue == true) ? 1234 : null; 

FAILS with: Type of conditional expression cannot be determined because there is no implicit conversion between 'int' and '<null>'.

So, you have to cast the null as well... This works:

int? myint = (testvalue == true) ? 1234 : (int?)null; 

UPDATE (Oct 2021):

As of C# 9.0 you can use "Target-Typed" conditional expresssions, and the example will now work as c# 9 can pre-determine the result type by evaluating the expression at compile-time.