Inner Join Using LINQ

Introduction

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

Question: What is inner join using LINQ?

In simple terms "It provides the flexibility to retrieve the matching result sets from two tables using a LINQ inner join." .

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

Step 2: The design of the Employee table looks like this:

Step 3: The design of the Department table looks like this:

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

<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="Default.aspx.cs" Inherits="LINQInnerJoinApp._Default" %>

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

</head>

<body>

<div>

<table>

<tr>

<asp:Label ID="Label1" runat="server" Text="INNER JOIN using LINQ" Font-Bold="true"

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

</td>

</tr>

<tr>

<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>

<br />

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

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

GridLines="None" AutoGenerateColumns="False">

</PagerStyle>

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

<asp:BoundField DataField="LastName" HeaderText="Last Name" />

<asp:BoundField DataField="DepartmentName" HeaderText="Department Name" />

</Columns>

</asp:GridView>

</td>

</tr>

</table>

</div>

</center>

</form>

</body>

</html>

Step 5: 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;

namespace LINQInnerJoinApp

{

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

{

protected void Page_Load(object sender, EventArgs e)

{

}

protected void Button1_Click(object sender, EventArgs e)

{

var query = from r in objEntities.Employeejoin p in objEntities.Department on r.EmpId equals p.EmpIdselect new{r.FirstName,r.LastName,p.DepartmentName};

GridView1.DataSource = query;

GridView1.DataBind();

}

#region

Instance MembersCompanyEntities objEntities = new CompanyEntities();

#endregion

}

Step 6: The output of the application looks like this:

Step 7: The results retrieved output of the application looks like this:

I hope this article is useful for you ...I look forward for your comments and feedback....Thanks Vijay Prativadi