使用实体框架5.0和xtragrid保存数据

我正在使用xtragrid来保存、加载和修改数据。现在切换到EF5后，它就不起作用了。尝试将我的代码更改为local和tobindinglist，但数据库中没有任何更改。有什么建议吗？

public partial class formKonstruksiyon : Form
{
    public Tank_Analizor_DBEntities db;
    public formKonstruksiyon()
    {
        InitializeComponent();
        db = new Tank_Analizor_DBEntities();
    }
    private void formKonstruksiyon_Load(object sender, EventArgs e)
    {
        konstruksiyonBindingSource.DataSource = db.Konstruksiyon.Local.ToBindingList();
        gridControl1.DataSource = konstruksiyonBindingSource.DataSource;
    }
    private void barButtonItemSave_ItemClick(object sender,
      DevExpress.XtraBars.ItemClickEventArgs e)
    {
        try
        {
            db.SaveChanges();
            LibStatic.ShowSuccessMessage();
        }
        catch (Exception ex)
        {
            LibStatic.ShowErrorMessage(ex);
        }
    }
    private void silToolStripMenuItem_Click(object sender, EventArgs e)
    {
        gridView1.DeleteRow(gridView1.FocusedRowHandle);
    }
}

更改后的一些更新：

 konstruksiyonBindingSource.DataSource = db.Konstruksiyon.ToList();
 private void barButtonItemSave_ItemClick(object sender, 
   DevExpress.XtraBars.ItemClickEventArgs e)
        {
            LibStatic.GridPostPendingRow(gridView1);
            try
            {
                konstruksiyonBindingSource.DataSource = db.Konstruksiyon.Local.ToBindingList();
                db.SaveChanges();
                LibStatic.ShowSuccessMessage();
            }
            catch (Exception ex)
            {
                LibStatic.ShowErrorMessage(ex);
            } 
        }

它有点保存：如果我只添加一个条目，它不会保存，但如果我添加两个条目，则会保存。这怎么可能呢？