CODEWITHSUNDEEP
c#datetimenull
twostrats
twostrats

Reputation: 1

Comparing DateTime variable to DateTime data type column with Null values in it

I have to do a c# search on records in an array from a sql server db using 3 data elements. One of the data elements has to be a DateTime element in a column called DateOfBirth. Unfortunately there are a lot of null values in this column and I can't figure out how to compare a DateTime variable to a field with NULL values. I see a lot of answers that appear to be close to what I need here, but nothing has helped. Thanks for any help, This has been my format. 

if ((DateTime)dt == (DateTime)temp[i].Individual.DateOfBirth)
    GlobalNum3.bnum3 = 1;

Upvotes: 0

Views: 123

Answers (2)

David Arno
David Arno

Reputation: 43254

I'm assuming that dt is already a DateTime, in which case it can't be null (DateTime is a struct) and there's no need to cast it.In addition, either temp[i].Individual.DateOfBirth is a DateTime too and so cannot be null either, or it's a Nullable<DateTime>.

Assuming both are DateTimes, DB nulls will be set to DateTime.MinValue, so just compare the values:

if (dt == (DateTime)temp[i].Individual.DateOfBirth)
{
    GlobalNum3.bnum3 = 1;
}

However, if temp[i].Individual.DateOfBirth is a Nullable<DateTime>, it might be null, or might simply have no value, so use it like this:

var possibleDateOfBirth = temp[i].Individual.DateOfBirth;
if (possibleDateOfBirth != null &&
    possibleDateOfBirth.HasValue &&
    dt == possibleDateOfBirth.Value)
{
    GlobalNum3.bnum3 = 1;
}

Upvotes: 1

T McKeown
T McKeown

Reputation: 12847

If you are querying the DB then try testing the nullable .HasValue property like this:

if (temp[i].Individual.DateOfBirth.HasValue && dt == temp[i].Individual.DateOfBirth.Value)
{
   GlobalNum3.bnum3 = 1;
}

Obviously I'm assuming you are testing DateTime? properties.

Upvotes: 0

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