Problem after adding row - not refreshing? RSS

• • Reply
  

  GeeksGoneBad

  Member

  129 Points

  57 Posts

  Problem after adding row - not refreshing?

  Feb 17, 2012 06:22 PM|LINK

  I have another weird one here... MVC3 and Entity Framework database first...

  I am making an app that's going to allow adding items from one list to another list (songs onto set lists to be exact)

  in the "edit" view is where I have "add to set list" links that link to a actionmethod that enters the row into the "SetListSongs" table - so far so good - the row gets added and everything works fine

  but when I return to the Edit View - the loop that lists the songs that are on the list is throwing an error - it "sees" that there is a new song (it's a foreach loop) but when it's trying to add the title from the song that was added it says "Object reference not set to an instance of an object."

  here's my controller action:

  public ActionResult AddSongToSetList(int setListID, int songID)
          {
              db.SetListSongs.Add(new SetListSong { SongID = songID, SetListID = setListID });
              db.SaveChanges();
   
              var setlist = db.SetLists.Find(setListID);
              ViewBag.UserID = new SelectList(db.aspnet_Users, "UserId", "UserName", setlist.UserID);
              ViewBag.BandID = new SelectList(db.Bands, "BandID", "BandName", setlist.BandID);
              ViewBag.Songs = db.Songs.Where(s => !(db.SetListSongs.Where(o => o.SetListID == setListID).Select(o => o.SongID)).Contains(s.SongID));
              
              return View("Edit",setlist);
          }
  
  and here's the loop that works through all the songs except the last one that was added!
  
  

  <table>
                  @if (Model.SetListSongs != null)
                  {
                      foreach (var song in Model.SetListSongs)
                      {
                          <tr>
                              <td>
                                  @song.Song.Title
                              </td>
                              <td>
                                  @Html.ActionLink("Remove From Set List", "RemoveFromSetList", new { setListSongid = song.ID, setListID = Model.SetListID})
                              </td>
                          </tr>
                      }
                  }
              </table>

  Check out my CNC projects and more at The Backyard Workshop
  • Edited by GeeksGoneBad on Feb 17, 2012 06:23 PM
  • Edited by GeeksGoneBad on Feb 17, 2012 06:23 PM
• • Reply
  

  ignatandrei

  All-Star

  135142 Points

  21676 Posts

  Moderator

  MVP

  Re: Problem after adding row - not refreshing?

  Feb 18, 2012 01:24 AM|LINK

  GeeksGoneBad

  it says "Object reference not set to an instance of an object."

  Which line? this one?

  GeeksGoneBad

   var setlist = db.SetLists.Find(setListID);

  My .NET blog : http://msprogrammer.serviciipeweb.ro/ |2012 Programmer tools
• • Reply
  

  GeeksGoneBad

  Member

  129 Points

  57 Posts

  Re: Problem after adding row - not refreshing?

  Feb 18, 2012 11:52 AM|LINK

  no the error is in the view on the line

   @song.Song.Title

  
  but it goes through 3 iterations (or how many songs there were before the add)
  just fine and errors on the third (the one that was added)

  it's almost like the database was updated with the number of rows that shouldbe there but not with the data that was addded or something

  Check out my CNC projects and more at The Backyard Workshop
• • Reply
  

  ignatandrei

  All-Star

  135142 Points

  21676 Posts

  Moderator

  MVP

  Re: Problem after adding row - not refreshing?

  Feb 18, 2012 06:01 PM|LINK

  GeeksGoneBad

  no the error is in the view on the line

   @song.Song.Title

  I do not understand why a song ( maybe a songviewmodel?!)have a song. Anyway, you can look in the database to see if there is a link with songid or prevent

  @if(song.Song == null)...

  My .NET blog : http://msprogrammer.serviciipeweb.ro/ |2012 Programmer tools
• • Reply
  

  GeeksGoneBad

  Member

  129 Points

  57 Posts

  Re: Problem after adding row - not refreshing?

  Feb 18, 2012 06:22 PM|LINK

  Thanks for the help - the model is actually a "Set List" and a Set List can have any number of Songs - so my loop is runnig through all of the songs on the set list and listing their titles

  the row is added to the database just fine - and if I go to the index view first and then back to the edit view everything works - but I don't want to have to go back to the index every time I add a song to a set list

  is there something that can be called to "refresh" the database in the app?

  Check out my CNC projects and more at The Backyard Workshop
• • Reply
  

  GeeksGoneBad

  Member

  129 Points

  57 Posts

  Re: Problem after adding row - not refreshing?

  Feb 20, 2012 04:51 PM|LINK

  I have verified that the row is entered into the database on the "SaveChanges" call

  and after the call I have verified that there's another row in the SetListSongs as you'd expect - but the data itself is not there!

  is there anyway to refresh the data in memory? I tried "Refresh" but it dosn't seem to exist in EF4? How do I refresh ?

  Check out my CNC projects and more at The Backyard Workshop
• • Reply
  

  ignatandrei

  All-Star

  135142 Points

  21676 Posts

  Moderator

  MVP

  Re: Problem after adding row - not refreshing?

  Feb 20, 2012 08:03 PM|LINK

  GeeksGoneBad

  How do I refresh ?

  reload from database.

  My .NET blog : http://msprogrammer.serviciipeweb.ro/ |2012 Programmer tools
• • Reply
  

  GeeksGoneBad

  Member

  129 Points

  57 Posts

  Re: Problem after adding row - not refreshing?

  Feb 20, 2012 08:17 PM|LINK

  I am already doing

  var setlist = db.SetLists.Find(setListID); 
  
  

  and passing the setlist back to the view - is there another way to reload from the database?

  Check out my CNC projects and more at The Backyard Workshop
• • Reply
  

  ignatandrei

  All-Star

  135142 Points

  21676 Posts

  Moderator

  MVP

  Re: Problem after adding row - not refreshing?

  Feb 20, 2012 08:33 PM|LINK

  close the db and re-open.

  My .NET blog : http://msprogrammer.serviciipeweb.ro/ |2012 Programmer tools
• • Reply
  

  GeeksGoneBad

  Member

  129 Points

  57 Posts

  Re: Problem after adding row - not refreshing?

  Feb 20, 2012 08:49 PM|LINK

  No dice - I tried adding

  db.Database.Connection.Close();

  after the savechanges and before the reloading of the SetLsit and it's still the exact same error

  here's a question - when i am passing the Setlist back to the view - it's a brand new view right? I mean there's no way that the previous view is still there and holding onto the old setlist model - right?

  Check out my CNC projects and more at The Backyard Workshop