In this article we will learn how to use
Substitution control in ASP.NET.
Substitution control
Substitution control is used to call a method
that returns a string in an output-cached page.
Properties: The main property of
the Substitution control is MethodName.
Figure 1.
MethodName - MethodName are Used to
assign method name that will fire each time page will load and return the
string. Please note that this method will be a static method.
For example: The below figure shows the
Substitution control.
Figure 2.
Now click on the source button of the design
form.
<%@ Page Language="vb" AutoEventWireup="false" CodeBehind="WebForm2.aspx.vb" Inherits="WebApplication34.WebForm2" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html>
<head id="Head1" runat="server">
<title>Post
Cache Substitution</title>
</head>
<body>
<form id="form1" runat="server">
<h4>
This page uses post cache substitution to insert a dynamic value
into a cached page.</h4>
<p>
DateTime using cheched:
<%= DateTime.Now.ToString()
%>
</p>
<p>
<b>DateTime
using Substitution:
<asp:Substitution ID="Substitution1" runat="server" MethodName="GetCurrentDate" />
</b>
</p>
</form>
</body>
</html>
Now double click on the form and create a
method GetCurrentDate calling through the MethodName property.
Shared Function GetCurrentDate(ByVal
context As
HttpContext) As
String
Return Now.ToString()
End Function
Now save and run the application.
Figure 3.