ARTICLE

Select Data From XML With Where Clause Using LINQ to XML

Posted by Vijay Prativadi Articles | XML October 16, 2012
Today, in this article let’s play around with one of the interesting and most useful concepts in LINQ to XML.
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Introduction

Today, in this article let's play around with one of the interesting and most useful concepts in LINQ to XML.

Question: What is select data from XML with where clause using LINQ to XML?

In simple terms "It provides flexibility to pull out the data from XML using a LINQ query by filtering the data based on element."

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


Output1.jpg
 

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

 

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

<Employees>

  <Employee>

    <FirstName>Vijay</FirstName>

    <Age>26</Age>

  </Employee>

  <Employee>

    <FirstName>Ram Reddy</FirstName>

    <Age>29</Age>

  </Employee>

</Employees>


Step 3:
The complete code of webform1.aspx looks like this:

 

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

    <title></title>

</head>

<body>

    <form id="form1" runat="server">

    <center>

        <div>

            <table>

                <tr>

                    <td colspan="2">

                        <asp:Label ID="Label1" runat="server" Text="Select Data with Where Clause 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">

                        <br />

                        <asp:GridView ID="GridView1" runat="server" BackColor="LightGoldenrodYellow" BorderColor="Tan"

                            BorderWidth="1px" CellPadding="2" EnableModelValidation="True" ForeColor="Black"

                            GridLines="None" AutoGenerateColumns="False">

                            <AlternatingRowStyle BackColor="PaleGoldenrod"></AlternatingRowStyle>

                            <FooterStyle BackColor="Tan"></FooterStyle>

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

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

                            </PagerStyle>

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

                            <Columns>

                                <asp:BoundField DataField="FirstName" HeaderText="First Name" ReadOnly="true" />

                                <asp:BoundField DataField="Age" HeaderText="Age" ReadOnly="true" />

                            </Columns>

                        </asp:GridView>

                    </td>

                </tr>

            </table>

        </div>

    </center>

    </form>

</body>

</html>


Step 4: The complete code of 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 LINQtoXMLSelectApp

{

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

    {

        protected void Page_Load(object sender, EventArgs e)

        {

        }

        protected void Button1_Click(object sender, EventArgs e)

        {

            XDocument document = XDocument.Load(@"c:\users\administrator\documents\visual studio 2010\Projects\LINQtoXMLSelectApp\LINQtoXMLSelectApp\Employee.xml");

            var query = from r in document.Descendants("Employee") where (int)r.Element("Age") > 27 select new

            {

                FirstName = r.Element("FirstName").Value, Age = r.Element("Age").Value };

            GridView1.DataSource = query;

            GridView1.DataBind();

        }

    }

}
 

Step 5: The output of the application looks like this:


 

Output2.png
 

 

Step 6: The filtered data selected from XML looks like this:

 Output3.png

I hope this article is useful for you.

 

Article Extensions
Contents added by Pankaj Kumar on May 30, 2013
Dear Sir,

I want to fetch/Select Data according to Id by passing/input through TextBox.

var query = from r in document.Descendants("Employee") where (int)r.Element("Age") > 27             it work fine

But I want
var query = from r in document.Descendants("Employee") where r.Element("Id") == TextBox4.Text   it do not work

Please give appropriate code.

Also

var updateQuery = from r in document.Descendants("Employee")where r.Element("Id").Value == TextBox4.Textselect r; it do not work

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