Using XPath to filter data from Database : XPath « XML « C# / CSharp Tutorial

1. C# / CSharp Tutorial
2. XML
3. XPath

using System;
using System.Data;
using System.Data.SqlClient;
using System.Xml;
using System.IO;

public class XPathSearch
{
    private static string connectionString = "Data Source=localhost;Initial Catalog=Northwind;Integrated Security=SSPI";

    public static void Main() 
    {
        string SQL = "SELECT CategoryID, CategoryName, Description FROM Categories";
        SqlConnection con = new SqlConnection(connectionString);
        SqlCommand com = new SqlCommand(SQL, con);
        SqlDataAdapter adapter = new SqlDataAdapter(com);
        DataSet ds = new DataSet("Northwind");

        con.Open();
        adapter.FillSchema(ds, SchemaType.Mapped, "Categories");
        adapter.Fill(ds, "Categories");
        con.Close();

        XmlDataDocument dataDoc = new XmlDataDocument(ds);

        string XPath;
        XPath = @"//Categories[starts-with(child::CategoryName, 'A')]";
        XmlNodeList nodes = dataDoc.DocumentElement.SelectNodes(XPath);

        foreach (XmlNode node in nodes)
        {
            foreach (XmlNode child in node.ChildNodes)
            {
                Console.WriteLine(child.InnerText);
            }
         }
    }
}