private void Department_Load(object sender, EventArgs e) { //dataGridView1.DataSource = departmentBUS.SelectALL(DataStatic.user,DataStatic.token); key = departmentBUS.GetKey(); List <String> listKey = new List <string>(); listKey.Add("Tất cả"); listKey.AddRange(key.LISTdepartment); comboBox1.DropDownStyle = ComboBoxStyle.DropDownList; comboBox1.DataSource = listKey; ShowDetail(); }