Linq for selecting using lambda expression

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Hi all,
I am newbie to linq expression so can anyone help with my problem?Let me explain, I have written a lambda expression for selecting all the details of function between a particular date and linq is :

C#

db.Meals.Where(c => c.MealDate== date && c.SessionID == SessionID && c.MealType == MealType ).FirstOrDefault();

see problem in my db the mealdate has both date and time and my date variable is only having date ,so I want to take only the date portion and neglect the time part.Any ideas,will be a great help to me.

Posted 13-Nov-12 22:47pm

Mani Zachariah

Updated 13-Nov-12 23:19pm

Herman<T>.Instance

v2

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Mohd. Mukhtar · Answer 1 · 2012-11-13T22:55:00

Solution 1

Hi,

Please formate the date according to your need.

modify your statement as below.

C#

db.Meals.Where(c => String.Format("{0:M/d/yyyy}", c.MealDate) == date && c.SessionID == SessionID && c.MealType == MealType ).FirstOrDefault();

Refer below links for formatting date in particular formate.

http://msdn.microsoft.com/en-us/library/az4se3k1.aspx[^]

http://www.mikesdotnetting.com/Article/23/Date-Formatting-in-CSharp[^]

http://www.csharp-examples.net/string-format-datetime/[^]

Posted 13-Nov-12 22:55pm

Mohd. Mukhtar

Updated 13-Nov-12 23:51pm

v6

Comments

Mani Zachariah 14-Nov-12 5:01am

Hi Mohd.Mukhtar,
Thanks for replying,but unfortunateky it dint work showing an error message like:
No overload for method 'ToString' takes 1 arguments
Can we use datetime.parse?

Mani Zachariah 14-Nov-12 5:12am

Any equivalent expression for ling:
select convert(varchar(10),'7/22/2012 12:00:00 AM',1) as [MM/DD/YYYY]

Mani Zachariah 14-Nov-12 5:13am

If there is then it will solve my problem.Please help?

Mohd. Mukhtar 14-Nov-12 5:32am

see the updated ans and refer given links for more details.

Mani Zachariah · Answer 2 · 2012-11-14T01:51:00

Solution 3

sorry a slight change...

SQL

CampCuisineDataContext db = new CampCuisineDataContext();
 return db.Meals.Where(c => (c.MealDate.Value - date).Days == 0 && (c.MealDate.Value - date).Hours > 0 && c.SessionID == SessionID && c.MealType == MealType).FirstOrDefault();

dis the final ans..
Thanks all

Posted 14-Nov-12 1:51am

Mani Zachariah

Comments

Nelek 14-Nov-12 16:27pm

Next time don't add a new solution. You can edit your previous messages if you click on the widget "improve question" / "improve solution". I delete the false one to avoid missunderstoods

Mani Zachariah 14-Nov-12 22:36pm

Sorry Nelek!!!I'm new to code project so dint know abt editing thing.

Matt T Heffron · Answer 3 · 2012-11-14T08:35:00

It seems Solution 3 still may have edge cases that don't match.
Just compare the .Date property on the DateTime values:

C#

CampCuisineDataContext db = new CampCuisineDataContext();
return db.Meals.Where(c => c.MealDate.Value.Date == date.Date &&
                           c.SessionID == SessionID &&
                           c.MealType == MealType).FirstOrDefault();

Also, your use of .Value on c.MealDate seems to imply that the MealDate column is nullable and the expression needs to check that it actually has a value.