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I get this error - Syntax error (missing operator) in query expression 'ProductArea = Hair Gel' This is my code -

using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Data;

using System.Drawing;

using System.Text;

using System.Windows.Forms;

using System.Data.OleDb;

namespace Salon_Order_A

{

    public partial class SummaryofOrders : Form

    {

        private int Hair; private OleDbCommand oleDbSelectCommand;

        /*==============================================*/

        /* MS Access connection string using Jet 4.0: */

        /*==============================================*/

        public static string connectionString = "provider=Microsoft.JET.OLEDB.4.0; " + "data source = " + Application.StartupPath + "\\SalonOrderDb.mdb";

        /*==============================================*/

        /* Define ADO .NET Objects */

        /*==============================================*/

        private OleDbDataAdapter dataAdapter;

        private DataSet dataSet;

        private DataTable dataTable;

        private OleDbConnection conn;

        /*==============================================*/

        /* Define Database Objects */

        /*==============================================*/

        private static string OrderNo;

        private static string ProductArea;

        private static string Consultant;

        private static string Total;

        public SummaryofOrders()

        {

            InitializeComponent();

            /*==============================================*/

            /* Default select command on the OrderNobers table */

            /*==============================================*/

            string commandstring = "select * from Orders";

            /*==============================================*/

            /* The link between the sql command and the database connection */

            /*==============================================*/

            dataAdapter = new OleDbDataAdapter(commandstring, connectionString);

            /*==============================================*/

            /* Define insert, update, and delete sql commands to use. */

            /*==============================================*/

            BuildCommands();

            /*==============================================*/

            /* Declare and fill the in-memory dataset from the database */

            /*==============================================*/

            dataSet = new DataSet();

            dataSet.CaseSensitive = true;

            dataAdapter.Fill(dataSet,"Orders");

            /*==============================================*/

            /* Show all rows in the listbox */

            /*==============================================*/

            Fill_lb();

        }

        /* End of SummaryOrders Method */

        /*==============================================*/

        /* Method - Show all rows in the OrderNobers table in the listbox */

        /*==============================================*/

        private void Fill_lb()

        {

            dataTable = dataSet.Tables[0];

            listBox.Items.Clear();

            foreach (DataRow dataRow in dataTable.Rows)

            {

                LoadBuffers(dataRow); listBox.Items.Add(OrderNo + "\t\t" + ProductArea + "\t\t" + Consultant + "\t\t" + Total);

            }

        }

        /*==============================================*/

        /* Method - Load global strings from column values in the datarow */

        /*==============================================*/

        private void LoadBuffers(DataRow prow)

        {

            OrderNo = prow["OrderNo"].ToString().Trim();

            ProductArea = prow["ProductArea"].ToString().Trim();

            Consultant = prow["Consultant"].ToString().Trim();

            Total = prow["Total"].ToString().Trim();

        }

        private void BuildCommands()

        {

            OleDbConnection connection = (OleDbConnection)dataAdapter.SelectCommand.Connection;

            /*==============================================*/

            /* Use the select command's connection again */

            /*==============================================*/

            /*==============================================*/

            /* Declare a reusable insert command with parameters */

            /*==============================================*/

            dataAdapter.InsertCommand = connection.CreateCommand();

            dataAdapter.InsertCommand.CommandText = "insert into Orders " + "(OrderNo, ProductArea, Consultant, Total) " + "values " + "(?, ?, ?, ?)";

            dataAdapter.InsertCommand.Parameters.Add("OrderNo", OleDbType.Char, 0, "OrderNo");

            dataAdapter.InsertCommand.Parameters.Add("ProductArea", OleDbType.Char, 0, "ProductArea");

            dataAdapter.InsertCommand.Parameters.Add("Consultant", OleDbType.Char, 0, "Consultant");

            dataAdapter.InsertCommand.Parameters.Add("Total", OleDbType.Char, 0, "Total");

#region

            /*==============================================*/

            /* Declare a reusable update command with parameters (required if update in databse is */

            /* is required) */

            /* dataAdapter.UpdateCommand = connection.CreateCommand(); */

            /* dataAdapter.UpdateCommand.CommandText = "update Orders " + "set ProductArea = ? " + */

            /* "set Consultant = ? " + "set Total = ? " + "where OrderNo = ? "; */

            /* dataAdapter.UpdateCommand.Parameters.Add("OrderNo", OleDbType.Char, 0, "OrderNo"); */

            /* dataAdapter.UpdateCommand.Parameters.Add("ProductArea", OleDbType.Char, 0, "ProductArea"); */

            /* dataAdapter.UpdateCommand.Parameters.Add("Consultant", OleDbType.Char, 0, "Consultant"); */

            /* dataAdapter.UpdateCommand.Parameters.Add("Total", OleDbType.Char, 0, "Total"); */

            /*==============================================*/

            /*==============================================*/

            /* Declare a reusable delete command with parameters */

            /* dataAdapter.DeleteCommand = connection.CreateCommand(); */

            /* dataAdapter.DeleteCommand.CommandText = */

            /* "delete from OrderNobers where OrderNo = ?"; */

            /* dataAdapter.DeleteCommand.Parameters.Add("OrderNo", OleDbType.Char, 0, "OrderNo"); */

            /*==============================================*/

#endregion

        }

        private void btnEnter1_Click_1(object sender, EventArgs e)

        {

            try

            {

                this.oleDbDataAdapter.SelectCommand.CommandText = "SELECT * FROM Orders WHERE ProductArea = " + this.cmbProduct.Text;

                //"DELETE FROM BookDb WHERE ISBN =" + this.isbn_textBox.Text;

                /*+ this.cmbProduct.Text;*/

                // clear the DataSet from the last operation dataSet11.Clear();

                this.oleDbDataAdapter.Fill(this.dataSet11.Tables["Orders"]);

            }

            catch (OleDbException exp)

            {

                MessageBox.Show(exp.ToString());

            }

            //copy the dataset in datatable object DataTable dataTable = dataSet11.Tables[0];

            //if the row count = 0 then the qurey return nothing

            if (dataTable.Rows.Count == 0)

                MessageBox.Show("Record not found");

        }

        private void button1_Click(object sender, EventArgs e)

        {

            this.Close();

        }

    }

    /* Class SummaryofOrders ends here */ }