Questions about httpruntime. cache and httpcontext. Current. Cache

Reposted from Jun. net

Someone has already said this topic. Related links:

Httpruntime. cache vs. httpcontext. Current. Cache
Http://weblogs.asp.net/pjohnson/archive/2006/02/06/437559.aspx

Httpcontext. cache and httpruntime. Cache
Http://blog.joycode.com/dotey/archive/2005/01/15/43091.aspx

What I want to talk about here is from another perspective:

I. Two implementationsCodeDifferences:
We use. Net reflector to view the cache attribute of the httpcontext class and see the following code:

  Public  Cache ...  {Get...{ReturnHttpruntime. cache ;}} 

Therefore, the two are completely consistent in code.

2. The difference between the two lies in httpcontext. Current

Use. Net reflector to view httpcontext. Current as follows:

  Public     Static  Httpcontext current  ... {Get...{Return(Contextbase. CurrentAsHttpcontext );}} 

The current static attribute of the contextbase class is as follows:

  Internal    Static     Object  Current  ... {Get...{ReturnCallcontext. hostcontext ;}} 

The Static Property hostcontext of the callcontext class is as follows:

  Public     Static    Object  Hostcontext  ...  {  Get    ...  {Illogicalcallcontext context1  = Thread. currentthread. getillogicalcallcontext ();  Object  Obj1  =  Context1.hostcontext;  If  (Obj1  =     Null  )  ... {Logicalcallcontext context2=Callcontext. getlogicalcallcontext (); obj1=Context2.hostcontext ;}    Return  Obj1 ;}  } 

Apparently, non-web application httpcontext. Current returns NULL because
Contextbase. Current as httpcontext, return null.

Contextbase. Current has a value, but because it is not a web application, the returned object cannot be converted to httpcontext, and null is returned.

Therefore, httpcontext. Current. cache can only be used for the cache of Web applications. It is closely related to httpcontext.

3. httpruntime. cache can be used for caching non-web applications.

For example, the following ConsoleProgramCan read and write the cache normally. Httpcontext. cache cannot be used here.

    Static     Void  Main (  String  [] ARGs)  ...  {System. Web. caching. cache C =  System. Web. httpruntime. cache;  If  (C  ! =     Null  )  ... {C. insert ("1","123141432432");ObjectO=C. Get ("1"); Console. writeline (o );}  Console. Readline ();}   

Conclusion,
1. httpruntime. cache is equivalent to a specific implementation class of cache, which is placed in the system. Web namespace. However, non-Web applications can also be used.
2. httpcontext. cache is the encapsulation of the preceding cache class. Because it is encapsulated in httpcontext, it can only be used in httpcontext, that is, it can only be used for Web applications.

To sum up, use httpruntime. cache instead of httpcontext. cache as much as possible.