Question

I’m trying to make a simple application form were user can input data like 'reservationid', 'bookid', 'EmployeeID' and 'reservedate'. Its from my program Library System. 'reservationid' is an auto increment primary key while the rest are BigInt50, NVarChar50 and DateTime10 respectively. So I’m having this error: Input String was not in a correct format. It worked fine a while ago until I modified the 'reservationid' to auto increment so where did I go wrong? I’ve attached a sample of my code behind.

Any help would be greatly appreciated! Thanks in advance!

namespace LibraryManagementSystemC4.User
{
    public partial class Reserving : System.Web.UI.Page
    {
        public string GetConnectionString()
        {
            return System.Configuration.ConfigurationManager.ConnectionStrings["LibrarySystemConnectionString"].ConnectionString;
        }
        //string reservationid
        private void ExecuteInsert(string bookid, string EmployeeID, string reservedate)
        {
            SqlConnection conn = new SqlConnection(GetConnectionString());

            string sql = "INSERT INTO BookReservation (reservationid, bookid, EmployeeID, reservedate) VALUES " + " (@reservationid, @bookid, @EmployeeID, @reservedate)";
            try
            {
                conn.Open();
                SqlCommand cmd = new SqlCommand(sql, conn);
                SqlParameter[] param = new SqlParameter[3];

                //param[0] = new SqlParameter("@reeservationid", SqlDbType.Int, 50);
                param[0] = new SqlParameter("@bookid", SqlDbType.BigInt, 50);
                param[1] = new SqlParameter("@EmployeeID", SqlDbType.NVarChar, 50);
                param[2] = new SqlParameter("@reservedate", SqlDbType.DateTime, 10);

                //param[0].Value = reservationid;
                param[0].Value = bookid;
                param[1].Value = EmployeeID;
                param[2].Value = reservedate;

                for (int i = 0; i < param.Length; i++)
                {
                    cmd.Parameters.Add(param[i]);
                }

                cmd.CommandType = CommandType.Text;
                cmd.ExecuteNonQuery();
            }

            catch (System.Data.SqlClient.SqlException ex)
            {
                string msg = "Insert error";
                msg += ex.Message;
                throw new Exception(msg);
            }

            finally
            {
                conn.Close();
            }
        }

        protected void Page_Load(object sender, EventArgs e)
        {
            if (reservationidTextBox != null)
            {
                //reservationidTextBox.Text
                ExecuteInsert(bookidTextBox.Text, EmployeeIDTextBox.Text, reservationidTextBox.Text);

                ClearControls(Page);
            }

            else
            {
                Response.Write("Please input ISBN");
                bookidTextBox.Focus();
            }

            {
                //get bookid from Book Details and Employee PIN from current logged-in user
                bookidTextBox.Text = DetailsView1.SelectedValue.ToString();
                EmployeeIDTextBox.Text = HttpContext.Current.User.Identity.ToString();
            }
        }

        public static void ClearControls(Control Parent)
        {
            if (Parent is TextBox)
            {
                (Parent as TextBox).Text = string.Empty;
            }

            else
            {
                foreach (Control c in Parent.Controls)
                    ClearControls(c);
            }
        }
    }
}

Answer 1

If reservationid is auto incremented then remove it from your insert query

string sql = "INSERT INTO BookReservation ( bookid, EmployeeID, reservedate) VALUES (@bookid, @EmployeeID, @reservedate)";

also try

            param[0].Value = Convert.ToInt64(bookid);
            param[1].Value = EmployeeID;
            param[2].Value = Convert.ToDate(reservedate);