private void AddBooks_Click(object sender, EventArgs e) { object BookName = BookName_TextBox.Text; Utils.CheckObjNotNull(BookName); object Genre = Convert.ToString(GenreComboBox.Text); Utils.CheckObjNotNull(Genre); object Author = AuthorTextBox.Text; Utils.CheckObjNotNull(Author); object Language = Convert.ToString(LanguageComboBox.Text); Utils.CheckObjNotNull(Language); object Publisher = PublisherTextBox.Text; Utils.CheckObjNotNull(Publisher); string SortBy = Convert.ToString(Sort_Combobox.Text); string SortOrder = Convert.ToString(SortOrder_Combobox.Text); if (String.IsNullOrEmpty(SortOrder) || SortOrder.StartsWith("A")) { SortOrder = "asc"; } else { SortOrder = "desc"; } DataTable dt = ControlObj.GetSearchedBook(BookName, Genre, Author, Language, Publisher); if (!(SortBy == "None") && !(String.IsNullOrEmpty(SortBy))) { if (SortBy == "Name") { SortBy = "BookName"; } dt.DefaultView.Sort = String.Concat(SortBy, " ", SortOrder); dt = dt.DefaultView.ToTable(); } dataGridView1.DataSource = dt; dataGridView1.Refresh(); }