check if null C# code example

Example 1: c# check that value is not null or 0

public static bool IsNullOrValue(this double? value, double valueToCheck)
{
    return (value??valueToCheck) == valueToCheck;
}

Example 2: if property is null then c#

The null-conditional operators are short-circuiting.
That is, if one operation in a chain of conditional member or element 
access operations returns null, the rest of the chain doesn't execute. 
In the following example, B is not evaluated if A evaluates to null 
and C is not evaluated if A or B evaluates to null:
CODE
------------------
A?.B?.Do(C);
A?.B?[C];