C# sqlite dataGridView interacting duplicates the data

private void dataGridView1_CellValueChanged(object sender, DataGridViewCellEventArgs e)
        {
            int row = e.RowIndex;

            // retrieveing the ID cell of the changed row
            DataGridViewCell IDcell = dataGridView1["ID", row];

            // check if selected row is an existing row or new one
            bool newRow = false;
            if (IDcell.Value.ToString().Length == 0)
                newRow = true;
            else
                newRow = false;


            if (con.State != ConnectionState.Open)
                con.Open();

            SQLiteCommand cmd = new SQLiteCommand();
            cmd.Connection = con;

            if (newRow)
            {
                string sql = @" insert into myTable(Name, Item)
                                values(@name, @item)";

                cmd.CommandText = sql;

                // setting parameters                
                cmd.Parameters.AddWithValue("@name", dataGridView1["Name", row].Value.ToString());
                cmd.Parameters.AddWithValue("@item", dataGridView1["Item", row].Value.ToString());
            }
            else
            {
                string sql = @" update myTable 
                                set
                                Name = @name,
                                Item = @item
                                where ID = @id";

                cmd.CommandText = sql;

                // setting parameters
                cmd.Parameters.AddWithValue("@name", dataGridView1["Name", row].Value.ToString());
                cmd.Parameters.AddWithValue("@item", dataGridView1["Item", row].Value.ToString());
                cmd.Parameters.Add("@id", DbType.Int32).Value = int.Parse(dataGridView1["ID", row].Value.ToString());
            }

            cmd.ExecuteNonQuery();

            con.Close();
        }