Substitution Control ASP.NET

Introduction

This article demonstrates an interesting and very useful concept in ASP.NET.

Question: What is substitution control?

In simple terms "This enables the dynamic update of a portion of a page based on a value received from the method".

Step 1: Create a new web application

Output1.jpg

Step 2: Add a method name for the substitution control

Output2.png

Step 3: The complete code of WebForm1.aspx is as in the following:

<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="WebForm1.aspx.cs" Inherits="SubstitutionControlASP.NET.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="Substitution Control - ASP.NET" Font-Bold="true"

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

                    </td>

                </tr>

                <tr>

                    <td>

                        <asp:Label ID="Label6" runat="server" Text="Please Enter FirstNumber" Font-Size="Large"

                            Font-Names="Verdana" Font-Italic="true"></asp:Label>

                    </td>

                    <td>

                        <asp:TextBox ID="TextBox4" runat="server"></asp:TextBox>

                    </td>

                </tr>

                <tr>

                    <td>

                        <asp:Label ID="Label2" runat="server" Text="Please Enter SecondNumber" Font-Size="Large"

                            Font-Names="Verdana" Font-Italic="true"></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="Addition" Font-Names="Verdana" Width="213px"

                            BackColor="Orange" Font-Bold="True" OnClick="Button1_Click" />

                    </td>

                </tr>

                <tr>

                    <td colspan="2" align="center">

                        <asp:Substitution ID="Substitution1" runat="server" MethodName="GetAdd" />

                    </td>

                </tr>

                <tr>

                    <td colspan="2" align="center">

                        <asp:Label ID="Label5" runat="server" Font-Bold="true" Font-Names="Verdana"></asp:Label>

                    </td>

                </tr>

            </table>

        </div>

    </center>

    </form>

</body>

</html>

Step 4: 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 SubstitutionControlASP.NET

{

    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(TextBox4.Text) || string.IsNullOrEmpty(TextBox1.Text))

            {

                Label5.Text = "Please Enter Some Values";

                Label5.ForeColor = System.Drawing.Color.Red;

            }

            else

            {

                a = int.Parse(TextBox4.Text);

                b = int.Parse(TextBox1.Text);

            }

        }

        static int a, b;

        public static String GetAdd(HttpContext context)

        {

            return (a + b).ToString();

        }

    }

}

Step 5: The output of the application is as in the following:


Output3.png

Step 6: The updated data output of the application is as in the following:


Output4.png



I hope this article was useful for you.

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