Question

I want to round a double? value so that if its value is 2.3 the result should be 2 but if the input is null then the result should be null.

Answer 1

There is no direct way to round a nullable double. You need to check if the variable has a value: if yes, round it; otherwise, return null.

You need to cast a bit if you do this using the conditional ?: operator:

double? result = myNullableDouble.HasValue
               ? (double?)Math.Round(myNullableDouble.Value)
               : null;

Alternatively:

double? result = null;
if (myNullableDouble.HasValue)
{
    result = Math.Round(myNullableDouble.Value);
}