Not built-in. Out of my head, I can think of these options:
A. Manage your own AppSetting on your config and check for it when creating your QueryParameters:
// register caching
CacheController.RegisterCache(string.Empty, new ResultsetCache());
// determine globally whether or not to use caching
var cachingEnabled = GetCachingEnabledFlagFromConfig();
var customers = new EntityCollection<CustomerEntity>();
using (var adapter = new DataAccessAdapter())
{
var parameters = new QueryParameters()
{
CollectionToFetch = customers,
FilterToUse = CustomerFields.Country == "USA",
CacheResultset = cachingEnabled,
CacheDuration = new TimeSpan(0, 0, 10) // cache for 10 seconds
};
adapter.FetchEntityCollection(parameters);
}
B. Create your own version of ResultsetCache that checks for that AppSeting (see A), so it knows whether or not to turn on/off _purgeTimer.Enabled at the ctor.