Introduction

This article demonstrates an interesting and very useful concept in LINQ-to-SQL.

Question: What is select data with LINQ-to-SQL via WCF service?

In simple terms "It provides flexibility in the selection of data from a DB using LINQ-to-SQL context via WCF Service".

Step 1: Create a new web application

LINQ-to-SQL1.png

Step 2: Create a new WCF service application

wcf2.png

Step 3: Adding a new LINQ-to-SQL

wcf3.png

LINQ-to-SQL2.png

LINQ-to-SQL3.png

Step 4: The complete code of IService1.cs is as in the following:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.Serialization;
using System.ServiceModel;
using System.ServiceModel.Web;
using System.Text;
namespace WCFServiceApp
{
// NOTE: You can use the "Rename" command on the "Refactor" menu to change the interface name "IService1"
//in both code and config file together.
 [ServiceContract]
public interface IService1
 {
[OperationContract]List<Employee> GetAllEmployees();
}
}

Step 5: The complete code of Service1.svc.cs is as in the following:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.Serialization;
using System.ServiceModel;
using System.ServiceModel.Web;
using System.Text;
namespace WCFServiceApp
{
// NOTE: You can use the "Rename" command on the "Refactor" menu to change the class name "Service1"
//in code, svc and config file together.
 public class Service1 : IService1
{
public List<Employee> GetAllEmployees()
{
var query = (from r in objContext.Employees select r);
return query.ToList();
}
 #region Instance MembersDataClasses1DataContext objContext = new DataClasses1DataContext();
 #endregion
 }
}

Step 6: Adding a service reference

wcf5.png

Step 7: The complete code of WebForm1.aspx is as in the following:

<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="WebForm1.aspx.cs" Inherits="SelectData_WCF_LINQtoSQL.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="Select Data with LINQ-to-SQL using WCF" 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" AutoGenerateColumns="False">
 <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" />
 <Columns>
 <asp:BoundField DataField="EmpId" HeaderText="Id" />
 <asp:BoundField DataField="FirstName" HeaderText="FirstName" />
 <asp:BoundField DataField="LastName" HeaderText="LastName" />
 <asp:BoundField DataField="Age" HeaderText="Age" />
 </Columns>
 </asp:GridView>
 </td>
 </tr>
 </table>
 </div>
 </center>
 </form>
</body>
</html>

Step 8: The complete code of WebForm1.aspx.cs is as in the following:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using SelectData_WCF_LINQtoSQL.ServiceReference1;
namespace SelectData_WCF_LINQtoSQL
{
public partial class WebForm1 : System.Web.UI.Page
 {
protected void Page_Load(object sender, EventArgs e){}
protected void Button1_Click(object sender, EventArgs e)
{
GridView1.DataSource = objClient.GetAllEmployees();
GridView1.DataBind();
}
 #region Instance MembersService1Client objClient = new Service1Client();
 #endregion
 }
}

Step 9: The output of the application is as in the following:

Output7.png

Step 10: The selected data output of the application is as in the following:

Output8.png

I hope this article was useful for you.