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Select Data With UDF Via LINQ-to-SQL

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.


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