private bool create_new_category()
        {
            try
            {

                category newCat = new category();
                newCat.category_name = txtCategoryName.Text;
                newCat.code = txtCode.Text;
                newCat.description = txtDescription.Text;
                newCat.owner = 0;
                newCat.created_at = DateTime.Now;
                database.categories.InsertOnSubmit(newCat);
                database.SubmitChanges();
                return true;
            }
            catch (Exception newCatError)
            {
                MessageBox.Show(newCatError.Message);
                return false;
            }

        }
 partial void Updatecategory(category instance);
 partial void Deletecategory(category instance);
 partial void Insertcategory(category instance);