public void SaveProducts()
    {
        TempSave _Save = new TempSave();
        _Save.Localization = _LocationLabel.Text + "," + _LocNumbLab.Text;
        string items = "";
        for (int i = 0; i < _ProductsGrid.Rows.Count; i++)
        {
            items += _ProductsGrid.Rows[i].Cells[1].Value.ToString();
            items += ",";
        }
        string Qnt = "";
        for (int i = 0; i < _ProductsGrid.Rows.Count; i++)
        {
            Qnt += _ProductsGrid.Rows[i].Cells[0].Value.ToString();
            Qnt += ",";
        }
        try
        {
            items = items.Remove(items.Length - 1, 1);
            Qnt = Qnt.Remove(Qnt.Length - 1, 1);
        }
        catch{}
        _Save.Items = items;
        _Save.Quantity = Qnt;

        IEnumerable<TempSave> _CheackTem;

        string Cheak_TempSave = "SELECT * FROM TempSave WHERE Localization='" + _Save.Localization + "'";

        using (MySqlConnection Con = new MySqlConnection("server=localhost; database=wintestbeta;user=root; password=;"))
        {
            Con.Open();
            _CheackTem = Con.Query<TempSave>(Cheak_TempSave);
            Con.Close();
        }

        if (_CheackTem.Count() == 0)
        {
            string _TempSave = "INSERT INTO TempSave (Localization,items,Quantity) VALUES('" + _Save.Localization + "','" + _Save.Items + "','" + _Save.Quantity + "')";

            using (MySqlConnection Con = new MySqlConnection("server=localhost; database=wintestbeta;user=root; password=;"))
            {
                Con.Open();
                Con.Query(_TempSave);
                Con.Close();
            }
        }
        else
        {
            string _TempDelete = "DELETE FROM TempSave WHERE Localization='" + _Save.Localization + "'";

            using (MySqlConnection Con = new MySqlConnection("server=localhost; database=wintestbeta;user=root; password=;"))
            {
                Con.Open();
                Con.Query(_TempDelete);
                Con.Close();
            }
            string _TempSave = "INSERT INTO TempSave (Localization,items,Quantity) VALUES('" + _Save.Localization + "','" + _Save.Items + "','" + _Save.Quantity+ "')";

            using (MySqlConnection Con = new MySqlConnection("server=localhost; database=wintestbeta;user=root; password=;"))
            {
                Con.Open();
                Con.Query(_TempSave);
                Con.Close();
            }

        }
    }

public class TempSave
{
    public int id { get; set; }
    public string Localization { get; set; }
    public string Items { get; set; }
    public string Quantity { get; set; }
}

+---------------------+
|Qnt|Description|Value|
+---------------------+

string items = "";
 for (int i = 0; i < _ProductsGrid.Rows.Count; i++)
 {
     items += _ProductsGrid.Rows[i].Cells[1].Value.ToString();
     items += ",";
 }

items = items.Remove(items.Length - 1, 1);

if (items.Length > 1)
    items = items.Remove(items.Length - 1, 1);

var rows = _ProductsGrid.Rows.Cast<DataRow>();
string items String.Join(";",
    rows.Select(x => Convert.ToString(x.Cells[1].Value)));

string query = "SELECT * FROM TempSave WHERE Localization=@Localization";

using (var cmd = new MySqlCommand(query, connection))
{
    cmd.Parameters.AddWithValue("@Localization", _Save.Localization);

    // ...
}

using (var reader = cmd.ExecuteReader())
{
    // ...
}

if (CheackTemDataAlreadyExists())
    DeleteCheackTemData();

InsertCheackTemData();