Question

I have a C# console application written using Visual Studio 2008.

My system culture is en-GB. I have a Linq query that looks like this:

var myDate = "19-May-2010";

var cus = from x in _dataContext.testTable
     where x.CreateDate == Convert.ToDateTime(myDate)
     select x;

The resulting SQL query generates and error because it returns the dates as “19/05/2010” which it interprets as an incorrect date. For some reason even though my system culture is set to en-GB it looks like it’s trying to intrepret it as a en-US date.

Any ideas how I get around this?

Edit: Thanks for the comments about magic strings and var abuse, but that’s not my problem. My problem is that in the conversion from Linq to SQL the dates are being interpreted as US format dates (19/05/2010 is being interpreted as: month nineteen, day 5 and year 2010) resulting in the following error:

System.Data.SqlClient.SqlException: The conversion of a char data type to a datetime data type resulted in an out-of-range datetime value

The where clause of the resulting SQL query looks like:

WHERE ([t0].[CreateDate] = '19/05/2010 00:00:00') 

Please note that the exact same Linq query works perfectly in LinqPad.

I’ve tried the following where clause:

where x.CreateDate == DateTime.Today

and still get the error.

Additional Information:

SQL Server Query Visualizer:

SELECT [t0].[field1], [t0].[field2], [t0].[field3] AS [field4], [t0].[field5]
FROM [dbo].[table] AS [t0]
WHERE ([t0].[CreateDateTime] = '19/05/2010 00:00:00') 

Original query:
SELECT [t0].[field1], [t0].[field2], [t0].[field3] AS [field4], [t0].[field5]
FROM [dbo].[table] AS [t0]
WHERE ([t0].[CreateDateTime] = @p0) 
-------------------------------
@p0 [DateTime]: 19/05/2010 00:00:00

---

LINQPad:

-- Region Parameters
DECLARE @p0 DateTime SET @p0 = '2010-05-19 00:00:00.000'
-- EndRegion
SELECT [t0].[field1], [t0].[field2], [t0].[field3] AS [field4], [t0].[field5]
FROM [table] AS [t0]
WHERE ([t0].[CreateDateTime] = @p0)

In the above I notice that LinqPad presents the date in a different format to VS.

Thanks.

Alan T

Answer 1

Don’t send local strings into the database and ask the database to convert those strings into DateTimes. Just don’t.

Originally:

var myDate = "19-May-2010"; 

var cus = from x in _dataContext.testTable 
  where x.CreateDate == Convert.ToDateTime(myDate) 
  select x; 

• Don’t abuse var.
• Separate actions you intend to occur in the database from actions you intend to occur locally

So…

string myInput = "19-May-2010";
DateTime myDate = Convert.ToDateTime(myInput);

IQueryable<TestTable> cus =
  from x in _dataContext.testTable
  where x.CreateDate == myDate
  select x;

---

In response to the update.

• It seems that your app is sending the rightly formatted date times, but it’s using a connection that expects wrongly formatted datetimes.
• You can change each connection or you can change the login’s defaults: http://support.microsoft.com/kb/173907