Today I found myself coding a fairly familiar pattern – checking whether there was an entry in the ASP.NET cache with a particular key, if not, executing a method and adding the result to the cache, and either way, returning the result.

I wondered whether there was a “nice” way to do this using generics and anonymous delegates. This is what I came up with…

public delegate T MethodExecution<T>();
public static T GetCachedMethod<T>(string key, DateTime absoluteExpiration, MethodExecution<T> method)
{
    if (HttpContext.Current.Cache[key] == null)
        HttpContext.Current.Cache.Insert(key,
            method(),
            null, absoluteExpiration, Cache.NoSlidingExpiration);

Now, to use this method,I could write the following to return a cached (by one day) result of the method SomeMethodThatReturnsADataSet.

return GetCachedMethod<DataSet>(key,DateTime.Now.AddDays(1),
                delegate() { return SomeMethodThatReturnsADataSet(myParam); });

I’m not sure whether this just makes things more obscure – any comments? 🙂