Pull Distinct Data Using LINQ-to-XML

Introduction
 
Today, in this article let's play around with one of the interesting and most useful concepts in XML.
 
Question: What is distinct operation using LINQ-to-XML?

In simple terms "It enables the filtering of duplicate data to pull out distinct data using LINQ to XML".

Step 1: Create a new "ASP.NET Web Application", as in:

New-project-in-VS.jpg

Step 2: The complete code of Employee.xml looks like this:

<?xml version="1.0" encoding="utf-8" ?>

<Employees>

  <Employee Id="1">

    <FirstName>Vijay</FirstName>

    <LastName>Prativadi</LastName>

    <Age>26</Age>

  </Employee>

  <Employee Id="1">

    <FirstName>Vijay</FirstName>

    <LastName>Prativadi</LastName>

    <Age>26</Age>

  </Employee>

  <Employee Id="1">

    <FirstName>Vijay</FirstName>

    <LastName>Prativadi</LastName>

    <Age>26</Age>

  </Employee>

  <Employee Id="2">

    <FirstName>Swetha</FirstName>

    <LastName>Prativadi</LastName>

    <Age>23</Age>

  </Employee>

  <Employee Id="2">

    <FirstName>Swetha</FirstName>

    <LastName>Prativadi</LastName>

    <Age>23</Age>

  </Employee>

</Employees> 
 
Step 3: The complete code WebForm1.aspx looks like this:

 

<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="WebForm1.aspx.cs" Inherits="RemoveDuplicateLINQtoXMLApp.WebForm1" %>

 

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="http://www.w3.org/1999/xhtml">

<head id="Head1" runat="server">

    <style type="text/css">

        .grid

        {

            margin-top: 50px;

        }

    </style>

    <title></title>

</head>

<body>

    <form id="form1" runat="server">

    <center>

        <div>

            <table>

                <tr>

                    <td colspan="2" align="center">

                        <asp:Label ID="Label1" runat="server" Text="Distinct Data using LINQ-to-XML" Font-Bold="true"

                            Font-Size="Large" Font-Names="Verdana" ForeColor="Maroon"></asp:Label>

                    </td>

                </tr>

                <tr>

                    <td colspan="2" align="center">

                        <asp:Button ID="Button1" runat="server" Text="Select Data" Font-Names="Verdana" Width="213px"

                            BackColor="Orange" Font-Bold="True" OnClick="Button1_Click" />

                    </td>

                </tr>

                <tr>

                    <td colspan="2" align="center">

                        <asp:GridView ID="GridView1" runat="server" CssClass="grid" BackColor="LightGoldenrodYellow"

                            BorderColor="Tan" BorderWidth="1px" CellPadding="2" ForeColor="Black" GridLines="None">

                            <AlternatingRowStyle BackColor="PaleGoldenrod" />

                            <FooterStyle BackColor="Tan" />

                            <HeaderStyle BackColor="Tan" Font-Bold="True" />

                            <PagerStyle BackColor="PaleGoldenrod" ForeColor="DarkSlateBlue" HorizontalAlign="Center" />

                            <SelectedRowStyle BackColor="DarkSlateBlue" ForeColor="GhostWhite" />

                            <sortedascendingcellstyle backcolor="#FAFAE7" />

                            <sortedascendingheaderstyle backcolor="#DAC09E" />

                            <sorteddescendingcellstyle backcolor="#E1DB9C" />

                            <sorteddescendingheaderstyle backcolor="#C2A47B" />

                        </asp:GridView>

                    </td>

                </tr>

            </table>

        </div>

    </center>

    </form>

</body>

</html>


Step 4: The complete code WebForm1.aspx.cs looks like this:

 

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

using System.Web.UI;

using System.Web.UI.WebControls;

using System.Xml.Linq;

namespace RemoveDuplicateLINQtoXMLApp

{

    public partial class WebForm1 : System.Web.UI.Page

    {

        protected void Page_Load(object sender, EventArgs e)

        {

        }

        protected void Button1_Click(object sender, EventArgs e)

        {

            XElement employee = XElement.Load(@"c:\users\administrator\documents\visual studio 2010\Projects\RemoveDuplicateLINQtoXMLApp\RemoveDuplicateLINQtoXMLApp\Employee.xml");

            var result = from r in employee.Descendants("Employee")

                         group r by (string)r.Attribute("Id") into p

                         select new

                             {

                                 FirstName = (string)p.Elements("FirstName").First(),

                                 LastName = (string)p.Elements("LastName").First(),

                                 Age = (int)p.Elements("Age").First()

                             };

            GridView1.DataSource = result;

            GridView1.DataBind();

        }

    }

}

Step 5: The output of application looks like this:


output-of-application-in-linq-to-xml.jpg

Step 6: The data retrieved output of application looks like this:


Retrieved-output-of-application-in-linq-to-xml.jpg

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