How can I use System.Web.Caching.Cache in a Console application?

Question

Context: .Net 3.5, C#
I'd like to have caching mechanism in my Console application.
Instead of re-inventing the wheel, I'd like to use System.Web.Caching.Cache (and that's a final decision, I can't use other caching framework, don't ask why).
However, it looks like System.Web.Caching.Cache is supposed to run only in a valid HTTP context. My very simple snippet looks like this:

using System; using System.Web.Caching; using System.Web;  Cache c = new Cache();  try {     c.Insert("a", 123); } catch (Exception ex) {     Console.WriteLine("cannot insert to cache, exception:");     Console.WriteLine(ex); } 

and the result is:

 cannot insert to cache, exception: System.NullReferenceException: Object reference not set to an instance of an object.    at System.Web.Caching.Cache.Insert(String key, Object value)    at MyClass.RunSnippet() 

So obviously, I'm doing something wrong here. Any ideas?

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Update: +1 to most answers, getting the cache via static methods is the correct usage, namely HttpRuntime.Cache and HttpContext.Current.Cache. Thank you all!

Answer 1

The documentation for the Cache constructor says that it is for internal use only. To get your Cache object, call HttpRuntime.Cache rather than creating an instance via the constructor.

Answer 2

While the OP specified v3.5, the question was asked before v4 was released. To help anyone who finds this question and can live with a v4 dependency, the framework team created a new general purpose cache for this type of scenario. It's in the System.Runtime.Caching namespace: http://msdn.microsoft.com/en-us/library/dd997357%28v=VS.100%29.aspx

The static reference to the default cache instance is: MemoryCache.Default