Type of conditional expression cannot be determined because there is no implicit conversion between System.DateTime and null

Question

DateTime tempDate = calculatesomedatetime();

someDateTimeControl.Value = null; //no issue

someDateTimeControl.Value = (tempDate > DateTime.MinValue)? tempDate : null;

Type of conditional expression cannot be determined because there is no implicit conversion between System.DateTime and null

Line 3 throwing me such error which I don't understand as the comparison is

(tempDate > DateTime.MinValue)

and

null

is just value assignment. Why would compiler interpret this as error?

However if I write as below, it has no problem

if(tempDate > DateTime.MinValue)

{

    someDateTimeControl.Value = tempDate;

}else

{

    someDateTimeControl.Value = null;

}

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Answer 1

The issue is with the ternary operation. You're changing the data type from DateTime to a nullable DateTime. Ternary operations require you to return the same data type both before and after the colon. Doing something like this would work:

someDateTimeControl.Value = (tempDate > DateTime.MinValue) ? (DateTime?)tempDate : null;

Type of conditional expression cannot be determined because there is no implicit conversion between System.DateTime and null

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