private void comboBox3_SelectedIndexChanged(object sender, EventArgs e) { if (comboBox3.ValueMember == "PartID") { DataTable dt = bllss4.getBatchByPartAndDes(int.Parse(comboBox1.SelectedValue.ToString()), int.Parse(comboBox3.SelectedValue.ToString())); comboBox4.DataSource = dt; comboBox4.DisplayMember = "BathNumber"; comboBox4.ValueMember = "BathNumber"; } }