caching Type.GetXYZ

Question

In a specific piece of code i cal Type.GetFields() many times. One call can call it 5 times or more. Also a piece of code could iterate thousands of times. ATM i dont need to optimize but i am asking so if i need to i know how.

How could i cache this? I am hoping i can do something like obj.GetType().Tag["myCacheId"] and pull out cached data. But i doubt i can do this. Can i attach data to a type somehow? i really hope i dont resort to a singleton. How might i cache data relating to Type's?

Answer 1

Just stick it in a FieldInfo[] somewhere, like at the beginning of your method or before your loop:

FieldInfo[] fields = Type.GetFields((BindingFlags.Public | 
    BindingFlags.Static | BindingFlags.Whatever));

Answer 2

The CLR already caches metadata. Very slow on the first call when it is dug out of the assembly, fast afterward. Caching yourself isn't going to make any difference.

Answer 3

If you have many Types, you could use a Dictionary to map from each type to the cached information for that type. (But this will only help if the dictionary lookup is faster than the Type.GetFields operation!)