Basic Civil Engineering first year Notes- Chapter 4 Building.pptx
Caching a page
1. Caching a ASP.NET Page
First, import the namespace of System.Web.Caching
using System.Web.Caching;
Declare the variables
static bool itemRemoved = false;
static CacheItemRemovedReason reason;
CacheItemRemovedCallback onRemove = null;
Define the method of AddItemToCache, it will use Cache.Add to add items to cache
public void AddItemToCache(Object sender, EventArgs e)
{
itemRemoved = false;
onRemove = new CacheItemRemovedCallback(this.RemovedCallback);
if (Cache["Key1"] == null)
Cache.Add("Key1", "Caching", null, DateTime.Now.AddSeconds(60), TimeSpan.Zero,
CacheItemPriority.High, onRemove);
}
Define the method of RemoveItemFromCache, it will use Cache.Remove to remove items from
cache
public void RemoveItemFromCache(Object sender, EventArgs e)
{
if (Cache["Key1"] != null)
Cache.Remove("Key1");
}
When using the method of Cache.Remove , it will be leaded to invoke RemovedCallback method
public void RemovedCallback(String k, Object v, CacheItemRemovedReason r)
{
itemRemoved = true;
reason = r;
}
2. Page_Load
protected void Page_Load(object sender, EventArgs e)
{
if (itemRemoved)
{
Response.Write("RemovedCallback event raised.");
Response.Write("<BR>");
Response.Write("Reason: <B>" + reason.ToString() + "</B>");
}
else
{
Response.Write("Value of cache key: <B>" + Server.HtmlEncode(Cache["Key1"] as string) + "</B>");
}
}
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>
![Caching a ASP.NET Page
First, import the namespace of System.Web.Caching
using System.Web.Caching;
Declare the variables
static bool itemRemoved = false;
static CacheItemRemovedReason reason;
CacheItemRemovedCallback onRemove = null;
Define the method of AddItemToCache, it will use Cache.Add to add items to cache
public void AddItemToCache(Object sender, EventArgs e)
{
itemRemoved = false;
onRemove = new CacheItemRemovedCallback(this.RemovedCallback);
if (Cache["Key1"] == null)
Cache.Add("Key1", "Caching", null, DateTime.Now.AddSeconds(60), TimeSpan.Zero,
CacheItemPriority.High, onRemove);
}
Define the method of RemoveItemFromCache, it will use Cache.Remove to remove items from
cache
public void RemoveItemFromCache(Object sender, EventArgs e)
{
if (Cache["Key1"] != null)
Cache.Remove("Key1");
}
When using the method of Cache.Remove , it will be leaded to invoke RemovedCallback method
public void RemovedCallback(String k, Object v, CacheItemRemovedReason r)
{
itemRemoved = true;
reason = r;
}](https://image.slidesharecdn.com/cachingapage-101116232117-phpapp02/85/Caching-a-page-1-320.jpg)
![Page_Load
protected void Page_Load(object sender, EventArgs e)
{
if (itemRemoved)
{
Response.Write("RemovedCallback event raised.");
Response.Write("<BR>");
Response.Write("Reason: <B>" + reason.ToString() + "</B>");
}
else
{
Response.Write("Value of cache key: <B>" + Server.HtmlEncode(Cache["Key1"] as string) + "</B>");
}
}
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>](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)