ASP.Net Entity Framework Add, Insert, Edit, Delete and Select

Here you can see how to work with ADO.NET Entity Framework and hand-coded access to data.

This code is implemented in the code-behind of the page, and associated to the buttons added to create a new element, edit n existing, save, cancel and delete.

For simplicity I am supposing that data entered in text boxes is correct, otherwise you can control using validation controls associated to the text boxes.

Saving a New or Edited existing: (Associated to Save Button)

         using (TheClubBDEntities myEntities = new TheClubBDEntities())
        {
            RaceType aRaceType;
            if (_Id == -1) //Save new
            {
                aRaceType = new RaceType();
                myEntities.RaceTypes.AddObject(aRaceType);
            }
            else
            { //Update existing
                aRaceType = (from r in myEntities.RaceTypes
                                       where r.Id == _Id
                                       select r).Single();             
            }
            aRaceType.Name = txbxNombre.Text;
            aRaceType.PuntosPart = Int32.Parse(txbxPuntos.Text);
            aRaceType.Memo = txbxMemo.Text;
            LastPos = _Id;  // Used to control position in the data base.
            myEntities.SaveChanges();

            GridView1.DataBind();  // To refresh data into GridView

            setNormalMode();  //Disable save button and put textboxes in readonly mode.
        }

Deleting existing:

        using (TheClubBDEntities myEntities = new TheClubBDEntities())
        {
            var aRaceType = (from r in myEntities.RaceTypes
                             where r.Id == _Id
                             select r).Single();


            myEntities.RaceTypes.DeleteObject(aRaceType);
            myEntities.SaveChanges();
        }
        GridView1.DataBind();
        setNormalMode();

Cancel editing or adding a new:

        using (TheClubBDEntities myEnt = new TheClubBDEntities())
        {
            var aRaceType = (from rt in myEnt.RaceTypes
                                         orderby rt.Name ascending
                                        where rt.Id == LastPos
                                        select rt).SingleOrDefault();

            if (aRaceType == null)
            {
                _Id = -1;
                LastPos = -1;
            }
            else
            {
                _Id = aRaceType.Id;
                txbxNombre.Text = aRaceType.Name;
                txbxPuntos.Text = aRaceType.PuntosPart.ToString();
                txbxMemo.Text = aRaceType.Memo;
            }
            setNormalMode();
        }

Selecting from the GridView and putting data into textboxes:

        _Id = Int32.Parse(GridView1.SelectedRow.Cells[1].Text);
        LastPos = _Id;
        txbxNombre.Text = GridView1.SelectedRow.Cells[2].Text;
        txbxPuntos.Text = GridView1.SelectedRow.Cells[3].Text;
        txbxMemo.Text = GridView1.SelectedRow.Cells[4].Text;
        setNormalMode();

Moving to first:

        using (TheClubBDEntities myEnt = new TheClubBDEntities())
        {

            var aRaceType = (from rt in myEnt.RaceTypes
                                         orderby rt.Name ascending
                                         select rt).FirstOrDefault();

            if (aRaceType == null)
                _Id = -1;
            else
            {               
                _Id = aRaceType.Id;
                LastPos = _Id;
                txbxNombre.Text = aRaceType.Name;
                txbxPuntos.Text = aRaceType.PuntosPart.ToString();
                txbxMemo.Text = aRaceType.Memo;
            }
        }

Loading the page:

        using (TheClubBDEntities myEnt = new TheClubBDEntities())
        {
            if (!Page.IsPostBack)
            {
                var aRaceType = (from rt in myEnt.RaceTypes
                                             select rt).FirstOrDefault();

                if (aRaceType == null)
                {
                    _Id = -1;
                    LastPos = -1;
                }
                else
                {
                    _Id = aRaceType.Id;
                    LastPos = _Id;
                    txbxNombre.Text = aRaceType.Name;
                    txbxPuntos.Text = aRaceType.PuntosPart.ToString();
                    txbxMemo.Text = aRaceType.Memo;
                }
            }
        }