Write records from List(of T) to Linq Problem : The Official Microsoft ASP.NET Forums

Reply

Write records from List(of T) to Linq Problem

Aug 15, 2012 04:12 PM|LINK

I have a problem writing multiple records to a SQL DB via Linq to SQL.

I have a list object that stores all the pages a user visits into a session variable. At the end of the session I write the contents out to sql. The sub is called from global.asax:

tracker.AddPage(Request.Url.ToString())

This calls the sub Addpage:

    Public Sub AddPage(ByVal pageName As String)
        'create a new page tracker item 

        Dim tp As New TrackerPages
        tp.pageurl = pageName
        tp.pagedate = Now
        _tpages.Add(tp)

    End Sub

OK all that works fine.

I can see all the object pages and the pageurl and pagedate values during debug.

The problem is when I try writing this at the end of the session. Only the last page record is ever written.

Here is the code:

        If Not IsNothing(tracker.TPages) Then
            Try
                Dim db As New trackerDCDataContext                      ' get reference to DB
                Dim trackerPage As New trackerPage_tbl              ' get reference to DB table

                Dim tpages As List(Of TrackerPages) = tracker.TPages
                Dim tp As TrackerPages

                For Each tp In tpages
                    'trackerPage.trackerPageGuid = trackerPageID.ToString
                    trackerPage.trackerPageURL = tp.
                    'trackerPage.trackerPageDate = tp.pagedate
                    'trackerPage.trackerPageID = pageid

                    db.trackerPage_tbls.InsertOnSubmit(trackerPage)
                Next

                db.SubmitChanges()

            Catch ex As Exception

           End Try
    End If

If I look at the table in sql only the last record is written.

The table in question (trackerPage_tbl) has an ID field (trackerPageID) which is the primary key and has identity enabled.

I am rather lost on this so would appreciate some wisdom. Ta

Thanks for your help.
Darren

http://www.darrenstreet.co.uk
http://www.nine9design.co.uk

Reply

Re: Write records from List(of T) to Linq Problem

Aug 17, 2012 01:27 AM|LINK

Hi,

Please move the db.SubmitChanges() into the For Each statement——

For Each tp In tpages
                    trackerPage.trackerPageGuid = trackerPageID.ToString
                    trackerPage.trackerPageURL = tp.
                    trackerPage.trackerPageDate = tp.pagedate
                    trackerPage.trackerPageID = pageid
                    db.trackerPage_tbls.InsertOnSubmit(trackerPage)
                    db.SubmitChanges()
Next

Reply

Re: Write records from List(of T) to Linq Problem

Aug 17, 2012 08:31 AM|LINK

Yes I tried that days ago and it made no difference.

I have a testbed of pages, Deafault, Contact, Services etc. If I run it and click on all three pages and examine the list I can see 3 instances. However when I write only the first (initial) page is written.

The trackPageID increments as expected.

Odd!

Thanks for your help.
Darren

http://www.darrenstreet.co.uk
http://www.nine9design.co.uk

Reply

Decker Dong ...

All-Star

118619 Points

18779 Posts

Re: Write records from List(of T) to Linq Problem

Aug 17, 2012 08:39 AM|LINK

Darrenst
I have a testbed of pages, Deafault, Contact, Services etc. If I run it and click on all three pages and examine the list I can see 3 instances. However when I write only the first (initial) page is written.

What does this mean？

And where have you written？

Reply

Darrenst

Member

42 Points

86 Posts

Re: Write records from List(of T) to Linq Problem

Aug 17, 2012 08:54 AM|LINK

If I look at the autos running the code I have noticed that the Identity field (not touched in the code) is being assigned the value &H0. That might explain why I am getting only one record inserted.

Thanks for your help.
Darren

http://www.darrenstreet.co.uk
http://www.nine9design.co.uk

Reply

Darrenst

Member

42 Points

86 Posts

Re: Write records from List(of T) to Linq Problem

Aug 17, 2012 09:12 AM|LINK

The session variable stores the URL of each page a user visits.

Therefore to test I need to simulate the actions of a visitor to visit separate pages so that the session variable (tracker) is updated and incremented with page urls.

I am confirming that the session object does indeed have this data stored in memory.

I am establishing that the data is indeed present and available to be written.

Unfortunatley when I apply the code to write to SQL only the first record in the session variable is infact written to the DB table.

Thanks for your help.
Darren

http://www.darrenstreet.co.uk
http://www.nine9design.co.uk