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Web caching technology in ASP.NET and VB.NET is helpful for popular website reducing its server workload and improving access times. This tutorial will show you how to use web caching save data to RAM, and improve data access times therefore.
Download the Full Working Version of this Project written with Visual Studio.NET VB.NET 2005 Here!
Looking for the C#.NET 2005 Version? Click Here!
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First, import the namespace of System.Web.Caching
| import System.Web.Caching |
Declare the variables
Shared itemRemoved As Boolean = False
Shared reason As CacheItemRemovedReason
Dim onRemove As CacheItemRemovedCallback |
Define the method of AddItemToCache, it will use Cache.Add to add items to cache
Public Sub AddItemToCache(ByVal sender As Object, ByVal e As EventArgs) Handles Submit1.ServerClick
itemRemoved = False onRemove = New CacheItemRemovedCallback(AddressOf Me.RemovedCallback) If (IsNothing(Cache("Key1"))) Then
Cache.Add("Key1", "Caching", Nothing, DateTime.Now.AddSeconds(30), TimeSpan.Zero, CacheItemPriority.High, onRemove) End If |
Define the method of RemoveItemFromCache, it will use Cache.Remove to remove items from cache
Public Sub RemoveItemFromCache(ByVal sender As Object, ByVal e As EventArgs) Handles Submit2.ServerClick
If (Not IsNothing(Cache("Key1"))) Then
Cache.Remove("Key1") End If |
When using the method of Cache.Remove , it will be leaded to invoke RemovedCallback method
Public Sub RemovedCallback(ByVal k As String, ByVal v As Object, ByVal r As CacheItemRemovedReason)
itemRemoved = True
reason = r End Sub |
Page_Load
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
If (itemRemoved) Then
Response.Write("Removed event raised.")
Response.Write("<BR>")
Response.Write("Reason: <B>" + reason.ToString() + "") Else
Response.Write("Value of cache key: <B>" + Server.HtmlEncode(CType(Cache("Key1"), String)) + "</B>") End If |
The HTML of the web page
<%@ Page Language="VB" AutoEventWireup="false" CodeFile="Default.aspx.vb" Inherits="_Default" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html>
<body>
<Form id="Form1" runat="server">
<input id="Submit1" type=submit OnServerClick="AddItemToCache" value="Add Item To Cache" runat="server"/>
<input id="Submit2" type=submit OnServerClick="RemoveItemFromCache" value="Remove Item From Cache" runat="server"/> </Form>
</body>
</html> |
Download the Full Working Version of this Project written with Visual Studio.NET VB.NET 2005 Here!
Looking for the C#.NET 2005 Version? Click Here!
Looking for more ASP.NET Tutorials? Click Here!
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