Hello Team, Please I have this error in my C# window form application, Kindly help.
private void cmbRoom_SelectedIndexChanged(object sender, EventArgs e) {
if (cmbRoom.SelectedIndex != -1) { ComboBox comboBox = (ComboBox)sender; DataRowView selectedRow = (DataRowView)comboBox.SelectedItem;
if (selectedRow != null) { string selectedValue = selectedRow["roomID"].ToString(); string sqlQuery = "SELECT rRate FROM tblRoom WHERE roomID = @selectedValue"; using (SqlConnection sqlConnection = new SqlConnection(con_string)) { sqlConnection.Open(); using (SqlCommand cmd = new SqlCommand(sqlQuery, sqlConnection)) { cmd.Parameters.AddWithValue("@selectedValue", selectedValue);
using (SqlDataAdapter da = new SqlDataAdapter(cmd)) { DataTable dt = new DataTable(); da.Fill(dt); if (dt.Rows.Count > 0) { txtRate.Text = dt.Rows[0]["rRate"].ToString(); } } } } }