using System;

using System.Data;

using System.Xml.Serialization;

​

public class Program

{

    public static void Main()

    {

        TestDS();

    }

​

    static DataTable CategoryTable;

    static DataTable SubCategoryTable;

    static DataTable SubtoSubCategoryTable;

    private static void TestDS()

    {

        DataSet ds = new DataSet();

        CategoryTable = new DataTable("Category");

        CategoryTable.Columns.Add(new DataColumn("CatID", Type.GetType("System.Int32")));

        CategoryTable.Columns.Add(new DataColumn("CategoryName", Type.GetType("System.String")));

        CategoryTable.PrimaryKey = new DataColumn[] { CategoryTable.Columns["CatID"] };

        ds.Tables.Add(CategoryTable);

        SubCategoryTable = new DataTable("SubCategory");

        SubCategoryTable.Columns.Add(new DataColumn("SubId", Type.GetType("System.Int32")));

        SubCategoryTable.Columns.Add(new DataColumn("SubCatName", Type.GetType("System.String")));

        SubCategoryTable.Columns.Add(new DataColumn("CatId", Type.GetType("System.Int32")));

        ds.Tables.Add(SubCategoryTable);

        SubtoSubCategoryTable = new DataTable("Subtosubcategory");

        SubtoSubCategoryTable.Columns.Add(new DataColumn("Id", Type.GetType("System.Int32")));

        SubtoSubCategoryTable.Columns.Add(new DataColumn("SubCatName", Type.GetType("System.String")));

        SubtoSubCategoryTable.Columns.Add(new DataColumn("SubId", Type.GetType("System.Int32")));

        ds.Tables.Add(SubtoSubCategoryTable);

        //add relations to the tables here

        ds.Relations.Add("CatSubCat", CategoryTable.Columns["CatID"], SubCategoryTable.Columns["CatId"]);

        ds.Relations["CatSubCat"].Nested = true;

        ds.Relations.Add("SubCatSubSubCat", SubCategoryTable.Columns["SubId"], SubtoSubCategoryTable.Columns["SubId"]);

        ds.Relations["SubCatSubSubCat"].Nested = true;

        fillRows(1, "Name1");

        fillRows(2, "Name2");

        fillRows(3, "Name3");

        fillRows(4, "Name4");

        fillRows1(1, "SubName1", 1);

        fillRows1(2, "SubName2", 1);

        fillRows1(3, "SubName3", 1);

        fillRows1(4, "SubName4", 2);

        fillRows1(5, "SubName5", 2);

        fillRows1(6, "SubName6", 3);

        fillRows2(1, "S_SubName1", 1);

        fillRows2(2, "S_SubName2", 1);

        fillRows2(3, "S_SubName3", 1);

        fillRows2(4, "S_SubName4", 2);

        fillRows2(5, "S_SubName5", 2);

        fillRows2(6, "S_SubName6", 3);

        //ds.WriteXml(@"C:\Temp\Product.xml");

        Console.WriteLine(ds.GetXml());

    }

    private static void fillRows(int CatID, string CategoryName)

    {

        DataRow dr;

        dr = CategoryTable.NewRow();

        dr["CatID"] = CatID;

        dr["CategoryName"] = CategoryName;

        CategoryTable.Rows.Add(dr);

    }

    private static void fillRows1(int SubId, string SubCatName, int CatId)

    {

        DataRow dr;

        dr = SubCategoryTable.NewRow();

        dr["SubId"] = SubId;

        dr["SubCatName"] = SubCatName;

        dr["CatId"] = CatId;

        SubCategoryTable.Rows.Add(dr);

    }

    private static void fillRows2(int Id, string SubCatName, int SubId)

    {

        DataRow dr;

        dr = SubtoSubCategoryTable.NewRow();

        dr["Id"] = Id;

        dr["SubCatName"] = SubCatName;

        dr["SubId"] = SubId;

        SubtoSubCategoryTable.Rows.Add(dr);

    }

}