One error when i del a Category. 

the report is:

Server Error in '/TimeTracker' Application.
--------------------------------------------------------------------------------

The DELETE statement conflicted with the REFERENCE constraint "FK_TimeTracker_TimeEntry_IssueTracker_ProjectCategories". The conflict occurred in database "C:\TIMETRACKER\APP_DATA\TIMETRACKER.MDF", table "dbo.aspnet_starterkits_TimeEntry", column 'CategoryId'.
The statement has been terminated.
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.Data.SqlClient.SqlException: The DELETE statement conflicted with the REFERENCE constraint "FK_TimeTracker_TimeEntry_IssueTracker_ProjectCategories". The conflict occurred in database "C:\TIMETRACKER\APP_DATA\TIMETRACKER.MDF", table "dbo.aspnet_starterkits_TimeEntry", column 'CategoryId'.
The statement has been terminated.

Source Error:

Line 636:                sqlCmd.Connection = cn
Line 637:                cn.Open()
Line 638:                sqlCmd.ExecuteScalar()
Line 639:
Line 640:            End Using

who can help me?Thanks very much!
 

 http://msdn.microsoft.com/en-us/library/aa276139(SQL.80).aspx

Refer this guide

http://msdn.microsoft.com/en-us/library/ms972955.aspx

Thank you for this link.

But my problem is not solve.Now i find a new issue also about Category. When I edit something ,then clink the button of "Edit",there have error:categoryName
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.NullReferenceException: categoryName

Source Error:

Line 322:
Line 323:            If String.IsNullOrEmpty(CategoryName) Then
Line 324:                Throw New NullReferenceException("categoryName")
Line 325:            End If
Line 326:
 

You can try this

If String.IsNullOrEmpty(CategoryName) Then
         //Here you can show the user friendly message like

         Response.Write("Please select CategoryName");

End If

Can you updated the status of your thread

Can you update the status of thread