DataSetRelation ships : DataSetRelation « ADO.net Database « ASP.NET Tutorial

<%@ Page language="c#" Inherits="DataSetRelationships" CodeFile="Default.aspx.cs" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" >
<HTML>
  <HEAD>
    <title>DataSetRelationships</title>
  </HEAD>
  <body>
    <form id="Form1" method="post" runat="server">
      <asp:Literal id="HtmlContent" runat="server"></asp:Literal>
    </form>
  </body>
</HTML>

File: Default.aspx.cs

using System;
using System.Collections;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Web;
using System.Web.SessionState;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;
using System.Text;
using System.Data.SqlClient;

public partial class DataSetRelationships : System.Web.UI.Page
{

  protected void Page_Load(object sender, System.EventArgs e)
  {
    string connectionString = "Data Source=localhost;Initial Catalog=Northwind;Integrated Security=SSPI";
    SqlConnection con = new SqlConnection(connectionString);

    string sqlCat = "SELECT CategoryID, CategoryName FROM Categories";
    string sqlProd = "SELECT ProductName, CategoryID FROM Products";

    SqlDataAdapter da = new SqlDataAdapter(sqlCat, con);
    DataSet ds = new DataSet();

    try
    {
      con.Open();
      da.Fill(ds, "Categories");
      da.SelectCommand.CommandText = sqlProd;
      da.Fill(ds, "Products");
    }
    finally
    {
      con.Close();
    }

    DataRelation relat = new DataRelation("CatProds",
      ds.Tables["Categories"].Columns["CategoryID"],
      ds.Tables["Products"].Columns["CategoryID"]);

    ds.Relations.Add(relat);

    StringBuilder htmlStr = new StringBuilder("");
    foreach (DataRow row in ds.Tables["Categories"].Rows)
    {
      htmlStr.Append("<b>");
      htmlStr.Append(row["CategoryName"].ToString());
      htmlStr.Append("</b><ul>");

      DataRow[] childRows = row.GetChildRows(relat);

      foreach (DataRow childRow in childRows)
      {
        htmlStr.Append("<li>");
        htmlStr.Append(childRow["ProductName"].ToString());
        htmlStr.Append("</li>");
      }
      htmlStr.Append("</ul>");
    }

    HtmlContent.Text = htmlStr.ToString();
  }

}
18.28.DataSetRelation
	18.28.1.	DataSetRelation ships