Question

I am building an appointment booking system web application in asp.net in VB,

Im simply trying to check whether an appointment has been made on a date selected from the calendar control. I am using Linq for the bindings but the format from the calendar is mmddyyyy when i need ddmmyyyy, my appointments entered int sql table as are 20/09/2012 10:00:00

trying to use a linq from p in db.apps
where p.date=mycontrol.selecteddate

does not yield results

some code added:-

 Dim myDate As Date = appCalender.SelectedDate



        Dim stat = From a In db.Appointments
                 Where a.dateAndTime = DateTime.Parse(myDate).ToString("ddMMyyyy")
                 Select New With {a.dateAndTime}

        Dim myList As List(Of String) = Nothing
        For Each a In stat

            myList.Add(a.dateAndTime)

        Next

        ListBox1.DataSource = myList
        ListBox1.DataBind()

im not sure if the code DateTime.Parse,,,, is right, there are many appoinments on the selected date which i select from the calendar but i think the DateTime format is not translating into SQL correctly

The appointment datatype in SQL is datetime

Answer 1

You aren’t comparing the same datatypes.

Where a.dateAndTime = DateTime.Parse(myDate).ToString("ddMMyyyy")

If the column in your database (and Linq) is a DateTime, the value on the right of the “=” is a string. It won’t match up. Try this?

Where a.dateAndTime = DateTime.Parse(myDate)

EDIT

Also, it looks like you are only getting the Date from your calendar, not the time:

Dim myDate As Date = appCalender.SelectedDate

But you say your dates are stored as “20/09/2012 10:00:00”

20/09/2012 10:00:00 != 20/09/2012 00:00:00

Which is probably what is happening.

Try this

Dim myDate As DateTime =  DateTime.Parse(appCalender.SelectedDate)

Dim stat = From a In db.Appointments
           Where a.dateAndTime >= myDate And a.dateAndTime < myDate.AddDays(1)
           Select New With {a.dateAndTime}