Concurrency and the ObjectDataSource Control, ConflictDetection: CompareAllValues / OverwriteChanges : ObjectDataSource « ADO.net Database « ASP.Net






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  3. ObjectDataSource

Concurrency and the ObjectDataSource Control, ConflictDetection: CompareAllValues / OverwriteChanges


<%@ Page Language="C#" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN"
"http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
<script runat="server">
    protected void srcProducts_Updated(object sender, ObjectDataSourceStatusEventArgs e)
    {
        if (e.Exception != null)
        {
            e.ExceptionHandled = true;
            lblError.Text = "Could not update record";
        }
    }
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head id="Head1" runat="server">
    <title>Show Conflict Detection</title>
</head>
<body>
    <form id="form1" runat="server">
    <div>

    <asp:Label
        id="lblError"
        EnableViewState="false"
        CssClass="error"
        Runat="server" />

    <asp:GridView
        id="grdProducts"
        DataSourceID="srcProducts"
        DataKeyNames="Id"
        AutoGenerateEditButton="true"
        Runat="server" />

    <asp:ObjectDataSource
        id="srcProducts"
        ConflictDetection="CompareAllValues"
        OldValuesParameterFormatString="original_{0}"
        TypeName="ConflictedProducts"
        SelectMethod="GetProducts"
        UpdateMethod="UpdateProduct"
        OnUpdated="srcProducts_Updated"
        Runat="server" />

    </div>
    </form>
</body>
</html>

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

<configuration>
  <connectionStrings>
    <add name="Products" 
         connectionString="Data Source=.\SQLEXPRESS;
         AttachDbFilename=|DataDirectory|MyDatabase.mdf;Integrated Security=True;User Instance=True" />
  </connectionStrings>
</configuration>








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