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