Declare you integer variable as nullable
eg: int? variable=0; variable=null;
int ? index = null;
public int Index
{
get
{
if (index.HasValue) // Check for value
return index.Value; //Return value if index is not "null"
else return 777; // If value is "null" return 777 or any other value
}
set { index = value; }
}
int does not allow null, use-
int? value = 0
or use
Nullable<int> value
You cannot set an int
to null
. Use a nullable int (int?
) instead:
int? value = null;
Use Null.NullInteger ex: private int _ReservationID = Null.NullInteger;
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;
public static int? Timesaday { get; set; } = null;
OR
public static Nullable<int> Timesaday { get; set; }
or
public static int? Timesaday = null;
or
public static int? Timesaday
or just
public static int? Timesaday { get; set; }
static void Main(string[] args)
{
Console.WriteLine(Timesaday == null);
//you also can check using
Console.WriteLine(Timesaday.HasValue);
Console.ReadKey();
}
The null keyword is a literal that represents a null reference, one that does not refer to any object. In programming, nullable types are a feature of the type system of some programming languages which allow the value to be set to the special value NULL instead of the usual possible values of the data type.
https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/keywords/null https://en.wikipedia.org/wiki/Null
Source: Stackoverflow.com