How do you assign null values to Date field in Linq : C#, VS

May 16, 2008 10:06am pdt

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1. sjturner2 18,250
2. CarlVerret 11,800
3. Ceiled 6,500
4. TheLearn... 4,500
5. GreenGhost 4,150
6. gardavis 3,000
6. Praesidium 3,000
8. ZachSmith 2,600
9. CMYScott 2,250
10. SteveH_UK 2,000
10. naspinski 2,000
10. SwissKnife 2,000
10. IndianOcean 2,000
10. Smart_Man 2,000
10. vb_jonas 2,000
10. Koocurrent 2,000
10. Fernando... 2,000
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03.16.2008 at 10:03PM PDT, ID: 23246195 | Points: 500

	[x] Attachment Details

How do you assign null values to Date field in Linq

Zones: Language Integrated Query - LINQ, .NET, C# Programming Language

Tags: C#, VS

I am trying to check a condition before assigning a value to a date field. If there is no value then I want to set it to null. The problem is when I attempt to do this I get the following error:

Error 9 Type of conditional expression cannot be determined because there is no implicit conversion

Entity e = (isInsert) ? new Entity() : ent.Entities.Single(en => en.entityTypeBN == CustomFunction.PotentialPatient && en.ID == pid && en.officeGroupID == Convert.ToInt32(Session["oid"]));
.
.
.
e.DOB = (txtDOBIntake.Text.Length > 0) ? DateTime.Parse(txtDOBIntake.Text) : null;

And when I attempt to replace the null with Nullable I get this error:
Error 9 'System.DBNull' is a 'type' but is used like a 'variable'

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Question Stats

Zone: Microsoft

Question Asked By: rufassa

Question Asked On: 03.16.2008

Participating Experts: 3

Points: 500

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03.17.2008 at 12:20AM PDT, ID: 21140270

karthika_cts:

this._Customer.Entity = null;
Did you have a look at this URL? if not, FYI
http://msdn2.microsoft.com/en-us/library/bb425822.aspx

03.17.2008 at 10:19AM PDT, ID: 21144202

Rank: Guru

vo1d:

what is the type of e.DOB ?

03.18.2008 at 05:36AM PDT, ID: 21150254

rufassa:

DOB is a Date Field

03.18.2008 at 05:41AM PDT, ID: 21150302

rufassa:

this._Customer.Entity = null;

This is the same as this:
e.DOB = (txtDOBIntake.Text.Length > 0) ? DateTime.Parse(txtDOBIntake.Text) : null;

Which seams to work on some data types (i.e. int) but not on a Date field. With a date it throws this:
Error 9 Type of conditional expression cannot be determined because there is no implicit conversion

03.18.2008 at 05:46AM PDT, ID: 21150337

rufassa:

Never mind I found a solution elsewhere:

... you can assign it DateTime.MinValue and then consider anything that equals DateTime.MinValue to be null.
http://p2p.wrox.com/topic.asp?TOPIC_ID=25481

03.18.2008 at 09:31AM PDT, ID: 21152844

ShimonYK:

in the ItemUpdating event for your control, set the e.NewValues("DateField") = Nothing

20080236-EE-VQP-29 / EE_QW_2_20070628