ASP.NET Cached Items Being Removed

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Lately some of the items I've been placing in cache in ASP.NET have been being removed. When I assigned a callback method to trap these removals, I saw that the reason for removal was "underused" -- ASP.NET was removing these items to free up memory because they weren't being used often.

To prevent this from happening, use the following value for the priority parameter of Cache.Add():
CacheItemPriority.NotRemovable

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