Distinct List of ShortDates from Linq Query?

[s1buick]

I need to fill a dropdown with a distinct list of ShortDates from a Linq query to an Oracle table but I haven't quite got it. Here's what I have come up with so far:


This first part gives me a list of distinct DateTimes down to the minute and second which is more detail than I want.

Code: Select all

var dates = (from those in db.RTPCR_CNDATs
                select those.UPLOADDATE).Distinct().OrderByDescending(d => d.Value).AsQueryable();

Returns:
...
{1/24/2012 12:54:15 PM}
{1/24/2012 12:54:14 PM}
{1/18/2012 3:50:56 PM}
{1/18/2012 3:50:55 PM}
... etc.

Then this second part gives me a list of short dates but they are not distinct and I'm not finding where and how to get that distinct list.

Code: Select all

var dateResults = from d in dates.ToList()
                    select new { d.Value }.Value.ToShortDateString();

Returns:
...
"1/24/2012"
"1/24/2012"
"1/18/2012"
"1/18/2012"
... etc.

Could someone please help a nube with the correct syntax for what seems like it should be a fairly common need?

Thanks!

[MariiaI]

The Distinct() method should be applied to short dates, i.e., after the ToShortDateString() method is invoked.
So, you can try do the second part this way:

Code: Select all

var dateResults = (from d in dates.ToList()
                   select new { d.Value }.Value.ToShortDateString()).Distinct();

JIC: the 'select new { d.Value }' construction is not safe; if one of objects in the list is null, it will cause an exception.

[s1buick]

Beautiful! Thank You!

In this case the UPLOADDATE field can't be null but, for future reference, are you suggesting something like this to make it "safe?"

Code: Select all

var dateResults = (from d in dates.ToList() where d.Value != null
                            select new { d.Value }.Value.ToShortDateString()).Distinct();

Just trying to pick up as much as I can as I go along.

Thanks

[MariiaI]

Try using d.HasValue instead of d.Value. Because if the object is null, d.Value will throw exception: System.InvalidOperationException.

Code: Select all

var dateResults = (from d in dates.ToList() where d.HasValue
                            select new {d.Value}.Value.ToShortDateString()).Distinct();

For more information, see http://msdn.microsoft.com/en-us/library/1t3y8s4s

JIC: As far as I can understand, this question does not apply to our products. Please use this forum for questions about LinqConnect only.

[s1buick]

Understood. Thank you for taking the time to help me out this time. Your answers have pointed me in the right direction and your time is greatly appreciated!

Thank you