ADO Database ASP.Net

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  4. Concurrency and the ObjectDataSource Control, ConflictDetection
<%@ Page Language="C#" %>
"http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">

    protected void srcProducts_Updated(object sender, ObjectDataSourceStatusEventArgs e)
    {
        if (e.Exception != null)
        {
            e.ExceptionHandled = true;
            lblError.Text = "Could not update record";
        }
    }



    Show Conflict Detection


    
    

            id="lblError"
        EnableViewState="false"
        CssClass="error"
        Runat="server" />
            id="grdProducts"
        DataSourceID="srcProducts"
        DataKeyNames="Id"
        AutoGenerateEditButton="true"
        Runat="server" />
            id="srcProducts"
        ConflictDetection="CompareAllValues"
        OldValuesParameterFormatString="original_{0}"
        TypeName="ConflictedProducts"
        SelectMethod="GetProducts"
        UpdateMethod="UpdateProduct"
        OnUpdated="srcProducts_Updated"
        Runat="server" />
    

    


File: ConflictedProducts.cs
using System;
using System.Data;
using System.Data.SqlClient;
using System.Web.Configuration;
public class ConflictedProducts
{
    private static readonly string _conString;
    public static SqlDataReader GetProducts()
    {
        SqlConnection con = new SqlConnection(_conString);
        SqlCommand cmd = new SqlCommand();
        cmd.Connection = con;
        cmd.CommandText = "SELECT Id,Title,Director FROM Products";
        con.Open();
        return cmd.ExecuteReader(CommandBehavior.CloseConnection);
     }
     public static void UpdateProduct(string title, string director, string original_title, string original_director, int original_id)
     {
        SqlConnection con = new SqlConnection(_conString);
        SqlCommand cmd = new SqlCommand();
        cmd.Connection = con;
        cmd.CommandText = "UPDATE Products SET Title=@Title,Director=@Director"
            + " WHERE Id=@original_Id AND Title=@original_Title AND Director=@original_Director";
        cmd.Parameters.AddWithValue("@Title", title);
        cmd.Parameters.AddWithValue("@Director", director);
        cmd.Parameters.AddWithValue("@original_Id", original_id);
        cmd.Parameters.AddWithValue("@original_Title", original_title);
        cmd.Parameters.AddWithValue("@original_Director", original_director);
        using (con)
        {
            con.Open();
            int rowsAffected = cmd.ExecuteNonQuery();
            if (rowsAffected == 0)
                throw new Exception("Could not update Product record");
        }
    }
    static ConflictedProducts()
    {
        _conString = WebConfigurationManager.ConnectionStrings["Products"]. ConnectionString;
    }
}
File: Web.config

  
             connectionString="Data Source=.\SQLEXPRESS;
         AttachDbFilename=|DataDirectory|MyDatabase.mdf;Integrated Security=True;User Instance=True" />