使用实体框架和DBContext重新加载和更新

好的，所以我尝试了一些东西，但一直被卡住。我曾经让更新按钮工作过，现在它不会更新了。删除按钮将工作并删除记录，但我无法在删除记录后刷新网格视图。我还希望在按下更新按钮并更新记录后重新加载gridview。这是我所拥有的：

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 = "";
        }
    }

添加按钮工作得很好，似乎只是在刷新网格视图

    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();
    }

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();
            }
        }
    }