Получаю ошибку при попытке сохранить изменения dataGridView

{
label3.Text = "rbt";
string script = "SELECT id, name, Model_preparation_R_Hr, Time_for_preparation_hr, Time_for_post_processing_hr, YZV_work FROM rbt;";
mycon = new MySqlConnection(connect);
mycon.Open();
MySqlDataAdapter ms_data = new MySqlDataAdapter(script, connect);
var cb = new MySqlCommandBuilder(ms_data);
cb.GetInsertCommand();
DataSet ds = new DataSet();
ms_data.Update(dataGridView1.DataSource as DataTable);
ms_data.InsertCommand = cb.GetInsertCommand();
ms_data.InsertCommand.CommandText += "; select * from rbt where id = last_insert_id();";
ms_data.InsertCommand.UpdatedRowSource = UpdateRowSource.FirstReturnedRecord;        
}

else if (comboBox1.SelectedItem == "Rash")
{
label3.Text = "rash";
string script = "SELECT id, name, Spirt_10_Litr, gloves, knife, detergent_PH11_Litr FROM rash;";
mycon = new MySqlConnection(connect);
mycon.Open();
MySqlDataAdapter ms_data = new MySqlDataAdapter(script, connect);
var cb = new MySqlCommandBuilder(ms_data);
cb.GetInsertCommand();
ms_data.Update(dataGridView1.DataSource as DataTable);
ms_data.InsertCommand = cb.GetInsertCommand();
ms_data.InsertCommand.CommandText += "; select * from rash where id = last_insert_id();";
ms_data.InsertCommand.UpdatedRowSource = UpdateRowSource.FirstReturnedRecord;
}

ms_data.Update(dataGridView1.DataSource as DataTable);

else if (comboBox1.SelectedItem == "rbt")
{
label3.Text = "rbt";
string script = "SELECT * FROM hardlight.rbt;";
mycon = new MySqlConnection(connect);
mycon.Open();
MySqlDataAdapter ms_data = new MySqlDataAdapter(script, connect);
SD.DataTable table = new SD.DataTable();
ms_data.Fill(table);
DataSet ds = new DataSet();
dataGridView1.DataSource = table;
mycon.Close();
ds.AcceptChanges();
}