Introduction
Today, in this article let's
play around with one of the interesting and most useful concept in XML.
Question: What
are joins using LINQ-to-XML?
In simple terms "It enables
perform a join between two XML files and retrieve the value into grid as a
result set".
Step 1: Create
a new WebForm project
![New-Project-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="2">
<FirstName>Swetha</FirstName>
<LastName>Prativadi</LastName>
<Age>23</Age>
</Employee>
<Employee
Id="3">
<FirstName>Ram</FirstName>
<LastName>Reddy</LastName>
<Age>30</Age>
</Employee>
</Employees>
Step 3: The
complete code of Department.xml looks like this:
<?xml
version="1.0"
encoding="utf-8"
?>
<Departments>
<Department
DepartmentId="1"
EmpId="1">
<DepartmentName>Admin</DepartmentName>
</Department>
<Department
DepartmentId="2"
EmpId="1">
<DepartmentName>HR</DepartmentName>
</Department>
<Department
DepartmentId="3"
EmpId="2">
<DepartmentName>IT</DepartmentName>
</Department>
</Departments>
Step 4: The
complete code WebForm1.aspx looks like this:
<%@
Page Language="C#"
AutoEventWireup="true"
CodeBehind="WebForm1.aspx.cs"
Inherits="JoinsusingLINQtoXMLApp.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="Joins 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 5: 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
JoinsusingLINQtoXMLApp
{
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 department =
XElement.Load(@"c:\users\administrator\documents\visual
studio 2010\Projects\JoinsusingLINQtoXMLApp\JoinsusingLINQtoXMLApp\Department.xml");
XElement employee =
XElement.Load(@"c:\users\administrator\documents\visual
studio 2010\Projects\JoinsusingLINQtoXMLApp\JoinsusingLINQtoXMLApp\Employee.xml");
var joinQuery = from
r in department.Descendants("Department")
join s in
employee.Descendants("Employee")
on (int)r.Attribute("EmpId")
equals (int)s.Attribute("Id")
select
new
{
EmpId = (int)s.Attribute("Id"),
FirstName = (string)s.Element("FirstName"),
LastName = (string)s.Element("LastName"),
Age = (int)s.Element("Age"),
DepartmentName = (string)r.Element("DepartmentName")
};
GridView1.DataSource = joinQuery;
GridView1.DataBind();
}
}
}
Step 6: The
output of application looks like this
![Join-using-linq.jpg]()
Step 7: The
data retrieved output of application looks like this
![Retrieved-Join-using-linq.jpg]()