private void Btn_AddCategorySave_Click(object sender, RoutedEventArgs e)
 {
     if (string.IsNullOrEmpty(TxtBx_CategorTitle.Text))
     {
         MessageBox.Show("Please enter a category name before clicking the Save button.");
     }
     else
     {
         CategoryModel category = new CategoryModel(TxtBx_CategorTitle.Text);
         category.AddToDb();
         Close();
     }
 }