private void BtnSavecategory(object sender, RoutedEventArgs e)
 {
     if (!txtCatId.Text.Equals(""))
     {
         Category c = new Category();
         c.CategoryID   = Int32.Parse(txtCatId.Text);
         c.CategoryName = txtCatName.Text;
         c.Description  = txtDescri.Text;
         da.EditCategory(c);
         MessageBox.Show("Category Updated");
         MainWindow mw = Application.Current.Windows.OfType <MainWindow>().FirstOrDefault();
         if (mw != null)
         {
             mw.MainFrame.Content = new ManageCategories();
         }
     }
 }