.net core database insertion error

cmd4 is having issue. I checked my data types and everything looks good. I added comment in cmd 4, the first comment is data type C# holds and second comment shows data type mysql holds:

updated code here:

private void SaveData(string s)
{
var company = comboBox1.Text.ToString();
int companyid = Convert.ToInt32(comboBox1.SelectedValue);
var vendor = comboBox2.Text.ToString();
int vendorid = Convert.ToInt32(comboBox2.SelectedValue);
var POID = textBox3.Text.ToString();
var expected_date = dateTimePicker2.Value.ToShortDateString();
var todaydate = DateTime.Today;
var itemPaymentNote = comboBox3.Text.ToString();
try
{
MySqlConnection con = new MySqlConnection(ConfigurationManager.AppSettings["RL_InventoryConnection"]);
if (con.State == ConnectionState.Closed)
con.Open();
MySqlCommand cmd = new MySqlCommand("select * from vendormaster where vendor_id= +'" + vendorid + "' ;", con);
MySqlDataReader dr1 = cmd.ExecuteReader();
string VcontName1="", Vcontphone1 = "", Vcontemail1 = "", VcontName2 = "", Vcontphone2 = "" , Vcontemail2 = "";
while (dr1.Read())
{
VcontName1 = dr1["vendor_contact_Name1"].ToString();
Vcontphone1 = dr1["vendor_contact_phone1"].ToString();
Vcontemail1 = dr1["vendor_contact_email1"].ToString();
VcontName2 = dr1["vendor_contact_Name2"].ToString();
Vcontphone2 = dr1["vendor_contact_phone2"].ToString();
Vcontemail2 = dr1["vendor_contact_email2"].ToString();
}
dr1.Close();
foreach (DataGridViewRow dr in dataGridView1.Rows)
{
var ItemTypeCell = dr.Cells[0].Value;
var ItemNameCell = dr.Cells[1].Value;
var ItemModelCell = dr.Cells[2].Value;
var DescriptionCell = dr.Cells[3].Value;
int QuantityCell = Convert.ToInt32( dr.Cells[4].Value);
double UnitPriceCell = Convert.ToDouble( dr.Cells[5].Value);
var OtherNotesCell = dr.Cells[6].Value;
var GSTCell = dr.Cells[7].Value;
var CGSTCell = dr.Cells[8].Value;
var SGSTCell = dr.Cells[9].Value;
double ItemTotalCell =Convert.ToDouble( dr.Cells[10].Value);
Console.WriteLine(s);
//var a = "N/A";
MySqlCommand cmd1 = new MySqlCommand("select * from categorymaster where category_name like '" + ItemTypeCell + "' ;", con);
MySqlDataReader dr2 = cmd1.ExecuteReader();
int ItemTypeCellValue=0;
while (dr2.Read())
{
ItemTypeCellValue = Convert.ToInt32(dr2["Cat_ID"]);
}
dr2.Close();
MySqlCommand cmd2 = new MySqlCommand("select bm.Brand_id, bm.Cat_id_fk, bm.Brand_name from brandmaster bm join categorymaster cm on cm.Cat_id =bm.Cat_id_fk where cm.Cat_id = " + ItemTypeCellValue + " and bm.Brand_name like '" + ItemNameCell + "' ;", con);
MySqlDataReader dr3= cmd2.ExecuteReader();
int ItemNameCellValue = 0;
while (dr3.Read())
{
ItemNameCellValue = Convert.ToInt32(dr3["Brand_id"]);
}
dr3.Close();
MySqlCommand cmd3 = new MySqlCommand("select mm.Model_name, mm.Model_id, mm.Brand_id_fk from modelmaster mm join brandmaster bm on bm.Brand_id = mm.Brand_id_fk join categorymaster cm on cm.Cat_ID = bm.Cat_id_fk where cm.Cat_id ='" + ItemTypeCellValue + "' and bm.Brand_id = '" + ItemNameCellValue + "' and mm.Model_name like '" + ItemModelCell + "';", con);
MySqlDataReader dr4 = cmd3.ExecuteReader();
int ItemModelCellValue = 0;
while (dr4.Read())
{
ItemModelCellValue = Convert.ToInt32(dr4["Model_id"]);
}
Console.WriteLine(ItemModelCellValue);
dr4.Close();
//MySqlCommand cmd1 = new MySqlCommand("insert into pomaster ( po_id,vendor_id_fk,user_id_fk,po_date,comp_id_fk,po_status,quantity,cost_per_unit,gst_percent,CGST, SGST,total_amount,payment_notes,other_notes,Vendor_Contact_name,Vendor_Contact_phone1,Vendor_Contact_email1,Vendor_Contact_person2,Vendor_Contact_phone2,Vendor_Contact_email2,expected_delivery_date,actual_delivery_date) values(+'" + POID + "', +'" + vendorid + "', 1, SYSDATE(), '" + companyid + "', '" + s + "', +'" + QuantityCell + "', '" + UnitPriceCell + "', '" + GSTCell + "', '" + CGSTCell + "','" + SGSTCell + "', '" + ItemTotalCell + "', '" + itemPaymentNote + "', '" + OtherNotesCell + "', '" + VcontName1 + "', '" + Vcontphone1 + "','" + Vcontemail1 + "', '" + VcontName2 + "', '" + Vcontphone2 + "', '" + Vcontemail2 + "', '" + expected_date + "', +'" + a + "' ;", con);
MySqlCommand cmd4 = new MySqlCommand("insert into pomaster ( po_id,vendor_id_fk,user_id_fk,po_date,comp_id_fk,Cat_ID_FK,Brand_id_fk,Model_id_fk, po_status,quantity,cost_per_unit,gst_percent,CGST, SGST,total_amount,payment_notes,other_notes,Vendor_Contact_name,Vendor_Contact_phone1,Vendor_Contact_email1,Vendor_Contact_person2,Vendor_Contact_phone2,Vendor_Contact_email2,expected_delivery_date,actual_delivery_date) values(@poid, @vendorid, @userid, @sysdate, @companyid,@itemtype ,@itemname ,@itemmodel, @postatus, @quantity, @unitprice, @GST,@CGSTCell,@SGSTCell, @ItemTotalCell, @itemPaymentNote, @OtherNotesCell, @VcontName1, @Vcontphone1,Vcontemail1, @VcontName2, @Vcontphone2, @Vcontemail2, @expected_date , @actual_delivery_date ", con);
cmd4.Parameters.AddWithValue("@poid", POID);// string // varchar
cmd4.Parameters.AddWithValue("@vendorid", vendorid);//int // int
cmd4.Parameters.AddWithValue("@userid", 1);//int // varchar
cmd4.Parameters.AddWithValue("@sysdate", todaydate) ;// date //date
cmd4.Parameters.AddWithValue("@companyid", companyid); // int // bigint
cmd4.Parameters.AddWithValue("@itemtype", ItemTypeCellValue); // int // int
cmd4.Parameters.AddWithValue("@itemname", ItemNameCellValue); // int // int
cmd4.Parameters.AddWithValue("@itemmodel", ItemModelCellValue); // int // int
cmd4.Parameters.AddWithValue("@postatus", s); // string // varchar
cmd4.Parameters.AddWithValue("@quantity", QuantityCell);//int // int
cmd4.Parameters.AddWithValue("@unitprice", UnitPriceCell);//double //double
cmd4.Parameters.AddWithValue("@GST", GSTCell); // string // varchar
cmd4.Parameters.AddWithValue("@CGSTCell", CGSTCell); // string // varchar
cmd4.Parameters.AddWithValue("@SGSTCell", SGSTCell); // string // varchar
cmd4.Parameters.AddWithValue("@ItemTotalCell", ItemTotalCell); // double //double
cmd4.Parameters.AddWithValue("@itemPaymentNote", itemPaymentNote);// string // varchar
cmd4.Parameters.AddWithValue("@OtherNotesCell", OtherNotesCell); // string // varchar
cmd4.Parameters.AddWithValue("@VcontName1", VcontName1); //string //varchar
cmd4.Parameters.AddWithValue("@Vcontphone1", Vcontphone1);//string //varchar
cmd4.Parameters.AddWithValue("@Vcontemail1", Vcontemail1);//string //varchar
cmd4.Parameters.AddWithValue("@VcontName2", VcontName2);//string //varchar
cmd4.Parameters.AddWithValue("@Vcontphone2", Vcontphone2);//string //varchar
cmd4.Parameters.AddWithValue("@Vcontemail2", Vcontemail2);//string //varchar
cmd4.Parameters.AddWithValue("@expected_date", expected_date); //date // date
cmd4.Parameters.AddWithValue("@actual_delivery_date", null); //date //date
cmd4.ExecuteNonQuery();
}
}
catch (Exception ex)
{
throw ex;
}
}

yes, the proper data is populating for these two variables. Attached the screenshot for the same.