Introduction

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

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

In simple terms "It enables selection of data with a User Defined Function (UDF) using LINQ-to-SQL communication".

Step 1: Create a new UDF

USE [Company]
GO
/****** Object: UserDefinedFunction [dbo].[GetEmployeeData] Script Date: 02/19/2013 21:59:53 ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
CREATE Function [dbo].[GetEmployeeData]
(@EmpId INT)
RETURNS TABLE
RETURNSelect [EmpId],[FirstName],[LastName],[Age]From [dbo].[tblEmployee]Where EmpId = @EmpId

Step 2: Create a new web application

LINQ-to-SQL1.png

Step 3: Adding LINQ-to-SQL classes

LINQ-to-SQL2.png

Step 4: Add a table and UDF onto the designer

LINQ-to-SQL3.png

Step 5: The complete code of WebForm1.aspx is as in the following:

<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="WebForm1.aspx.cs" Inherits="SelectDataUDF_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">
 <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 UDF via LINQ-to-SQL" Font-Bold="true" Font-Size="Large" Font-Names="Verdana"
ForeColor="Maroon"></asp:Label></td>
 </tr>
 <tr>
 <td>
 <asp:Label ID="Label2" runat="server" Text="Please Enter Id" Font-Bold="true" Font-Names="Verdana"></asp:Label></td>
 <td>
 <asp:TextBox ID="TextBox1" runat="server"></asp:TextBox></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" />
 <EmptyDataTemplate>No Records Found!</EmptyDataTemplate>
 </asp:GridView>
 </td>
 </tr>
 <tr>
 <td colspan="2" align="center">
 <asp:Label ID="Label3" runat="server" Font-Bold="true" Font-Names="Verdana"></asp:Label></td>
 </tr>
 </table>
 </div>
 </center>
 </form>
</body>
</html>

Step 6: 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;
namespace SelectDataUDF_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)
{
if (string.IsNullOrEmpty(TextBox1.Text))
{
Label3.Text = "Please Enter Some Values";
Label3.ForeColor = System.Drawing.Color.Red;
}
else
 {
var query = objContext.GetEmployeeData(int.Parse(TextBox1.Text));
GridView1.DataSource = query;
GridView1.DataBind();
Label3.Text = "Data Retrieved Successfully";
Label3.ForeColor = System.Drawing.Color.Green;
TextBox1.Text = string.Empty;
}
}
 #region Instance MembersDataClasses1DataContext objContext = new DataClasses1DataContext();
 #endregion
 }
}

Step 7: The output of the application is as in the following:

LINQ-to-SQL4.png

Step 8: The selected data output of the application is as in the following:

LINQ-to-SQL5.png

I hope this article was useful for you.