在实体框架中使用泛型进行缓存

Question

I am using Cache pattern with Entity Framework and my problem is that for the Azure caching service I need data serialized. Which basically means that I need to call ToList() to be able to data to the cache (see comment in the code to locate correct line).

Entity Framework's data is in the ObjectSet<T> and it's base class is System.Data.Objects.ObjectQuery<TEntity> . Should I have somehow say in the method definition (RetrieveCachedData) that T is based on that one or how I can access ToList method?

protected T RetrieveCachedData<T>(string cacheKey, Func<T> fallbackFunction, CacheItemPolicy cachePolicy) where T : class
{            
    var cache = new AzureCache().GetCache();
    var data = cache.Get(cacheKey) as T;

    if (data != null)
    {
        return data;
    }

    data = fallbackFunction();
    if (data != null)
    {
        // I need to call .ToList() here to be able to add it to the cache
        cache.Add(cacheKey, data); 
    }
    return data;
}

Thanks!

Answer 1

正如实体框架中所述：ObjectSet及其（泛型）方差使用OfType<T>方法。