Reloading and Updating using Entity Framework and DBContext

Question

Ok so I have tried a few things and keep getting stuck. I had the update button working at one point and now it will not update. The delete button will work and delete records but I can not get the gridview to refresh after the record is deleted. I also want the gridview to reload after the update button is pressed and the record is updated. Here is what I have:

protected void btnDelete_Click(object sender, EventArgs e)
        {
            switch (btnDelete.Text)
            {
                case DeleteButton:
                    try
                    {
                        if (txtLocationName.Text != null && txtSubAccountName.Text != null)
                        {
                            Location locationCheck = _context.Locations.ToList()
                                                    .First(x => x.Name == txtLocationName.Text && x.SubAccount == txtSubAccountName.Text);
                            if (locationCheck != null)
                            {
                                Location n = new Location
                                {
                                    Id = grdvwLocationList.SelectedIndex,
                                    Name = txtLocationName.Text,
                                    SubAccount = txtSubAccountName.Text
                                };

                                _context.Locations.Remove(n);
                                _context.SaveChanges();



                            }
                        }
                    }
                    catch (Exception)
                    {
                        lblLocationNameNotification.Text = "Please type in a location/sub-account or select a location/sub-account that doesn't have a asset to delete.";
                        txtLocationName.Text = "";
                        txtSubAccountName.Text = "";
                    }
                    break;
                case CancelButton:
                    Reload();
                    break;
            }
        }





    public void PopulateLocationGridView()
    {
        var locations = _context.Locations.Where(l => l.CompanyId == CompanyId)
                        .OrderBy(l => l.Name)
                        .ToList();

        grdvwLocationList.DataSource = locations;
        grdvwLocationList.DataBind();

        if (locations.Count > 0)
        {
            grdvwLocationList.SelectedIndex = 0;
            RowSelected();
        }
        else
        {
            txtLocationName.Text = "";
            txtSubAccountName.Text = "";
        }
    }

The add button works just fine it just seems to be refreshing the grid view

Answer 1

After working on it last night I knew there was something that I was missing. I ended up going about it like this:

protected void btnDelete_Click(object sender, EventArgs e)
    {
        try
        {
            _context = new IMSDBContext();

            switch (btnDelete.Text)
            {
                case DeleteButton:
                    if (txtLocationName.Text != null && txtSubAccountName.Text != null)
                    {
                        Location location = _context.Locations.ToList()
                                            .First(x => x.Name == txtLocationName.Text && x.SubAccount == txtSubAccountName.Text);

                        _context.Locations.Remove(location);
                        _context.SaveChanges();

                        PopulateLocationGridView();
                        grdvwLocationList.SelectedIndex = 0;
                        RowSelected();
                    }
                    break;

                case CancelButton:
                    Reload();
                    break;
            }
        }
        catch (Exception ex)
        {
            lblLocationNameNotification.Text = ex.Message;
        }
        finally
        {
            if (_context != null)
            {
                _context.Dispose();
            }
        }
    }

I had tried to use the PopulateLocationGridView() and RowSelect() methods by themselves and it was still having trouble. I ended up putting in the grdvwLocationList.SelectedIndex = 0; in to set the selected index on the first index in the list instead of the index of the record that I just deleted. That is where I was having trouble. I thought that the SelectRow() would reselect the index again but I had to reset it back to another index. If there are any questions or comments please feel free. I am still learning and would like all of the advise that I can get.

Answer 2

I have the following exampe working in a winforms application The trick is the dset.local

    private void Form1_Load(object sender, EventArgs e)
    {
        var dset = Db.Tasks;   // Db is my context.
        DbSet<Task> qry = dset;
        qry.Load();
        bindingSource1.DataSource  =dset.Local.ToBindingList();

    }

    private void Form1_FormClosing(object sender, FormClosingEventArgs e)
    {
        Debug.Print(Db.Tasks.Count().ToString());
        bindingSource1.EndEdit();

        Db.SaveChanges();
    }