Httpcontext. Current. cache and httpruntime. Cache

This article from the csdn blog, reproduced please indicate the source: http://blog.csdn.net/avon520/archive/2009/11/25/4872704.aspx

 

In. net, cache has two calling methods: httpcontext. Current. cache and httpruntime. cache. What are the differences between the two methods? Let's take a look at the explanations on msdn:
Httpcontext. Current. cache: gets the cache object for the current HTTP request.
Httpruntime. cache: Get the current applicationProgram.

We can use the. NET reflector tool to check the implementation of httpcontext. cache and httpruntime. cache:

Httpcontext. cache and httpruntime. cache implementation
// System. Web. httpcontext. cache attribute implementation
Public sealed class httpcontext
{
Public Cache
{
Get
{
Return httpruntime. cache;
}
}
}

// System. Web. httpruntime. cache attribute implementation
Public sealed class httpruntime
{
Public static Cache
{
Get
{
If (aspinstalldirectoryinternal = NULL)
{
Throw new httpexception (Sr. getstring ("aspnet_not_installed", new object [] {versioninfo. systemwebversion }));
}
Cache cache = _ theruntime. _ cachepublic;
If (Cache = NULL)
{
Cacheinternal = cacheinternal;
Cachesection = runtimeconfig. getappconfig (). cache;
Cacheinternal. readcacheinternalconfig (cachesection );
_ Theruntime. _ cachepublic = cacheinternal. cachepublic;
Cache = _ theruntime. _ cachepublic;
}
Return cache;
}
}
}

Through the aboveCodeWe can see that httpcontext. Current. cache is implemented by calling httpruntime. cache, and the two point to the same cache object. Are there any differences between the two? Since the two point to the same cache object, the difference between the two can only appear in httpcontext and httpruntime. Let's take a look at the definitions of httpcontext and httpruntime in msdn.
Httpcontext: encapsulate all http-specific information about individual HTTP requests. httpcontext. Current is the current HTTP request to obtain the httpcontext object.

 

Httpruntime: provides a set of ASP. NET runtime services for the current application.

The preceding definition shows httpruntime. the cache is equivalent to a specific implementation class of the cache, although this class is placed in the system. httpcontext. current. cache is the encapsulation of the preceding cache class. Because it is encapsulated into the httpcontext class, it can only be used in the httpcontext class, that is, it can only be used for Web applications.

The following example demonstrates this:

Example of httpcontext. cache and httpruntime. Cache
Class cachetest
{
Static void main (string [] ARGs)
{
System. Web. caching. cache httpruntimecache = system. Web. httpruntime. cache;
Httpruntimecache. insert ("httpruntimecache", "I am stored in httpruntime. cache ");

If (httpruntimecache! = NULL)
{
Console. writeline ("httpruntimecache:" + httpruntimecache ["httpruntimecache"]);
}

System. Web. httpcontext = system. Web. httpcontext. Current;
If (httpcontext = NULL)
{
Console. writeline ("httpcontext object is null in console project ");
}
Else
{
System. Web. caching. cache httpcontextcache = httpcontext. cache;
Httpcontextcache. insert ("httpcontextcache", "I am stored in httpruntime. cache ");
If (httpcontextcache = NULL)
{
Console. writeline ("httpcontextcache is null ");
}
}

Console. Readline ();
}
}

Output result: httpruntimecache: I am stored in httpruntime. Cache
Httpcontext object is null in console Project

To sum up, we try to use httpruntime. cache when using the cache, which reduces both errors and callback function calls.

References: questions about httpruntime. cache and httpcontext. Current. cache, httpruntime. cache vs. httpcontext. Current. Cache

This article from the csdn blog, reproduced please indicate the source: http://blog.csdn.net/avon520/archive/2009/11/25/4872704.aspx