public void loadData() { dataGridView1.DataSource = HangBUS.loadAllDataHang(); (dataGridView1.Columns["MaLoai"] as DataGridViewComboBoxColumn).DataSource = loaiHang; (dataGridView1.Columns["MaLoai"] as DataGridViewComboBoxColumn).DisplayMember = "TenLoai"; (dataGridView1.Columns["MaLoai"] as DataGridViewComboBoxColumn).ValueMember = "MaLoai"; }