How do you learn a class hierarchy quickly?

Something I don't enjoy about programming is learning a new API. For example, right now I'm trying to learn Windows Identity Foundation. Its frustrating because I'm going to spend the bulk of the time learning how a few classes work and actually only write several lines of code.

In .NET, there are so many types that I seem to spend more time hunting around in msdn for a class than writing code. It also interrupts my workflow while I'm working because I have to type a little bit than look something up.

Obviously, I don't have to do this for the basic classes. Whenever new things come though there is definitely some looking up to do. Then I often don't reuse that class enough to really review it or bring it into action.

I'm wondering if anybody out there has a found a way to memorize (or look up more efficiently) these object model hierarchies?

Solution

I was in your position as well long time ago when I learned Java and its Collection classes (or SWING, or AWT for that matter).

Here are a few steps I did and the outcome of those steps:

Didn't bother to take notes, keep on using it => only remember the most used class
Take an unorganized notes => same result, remember the most used class
Simple class diagrams => improvement, but incomplete
Simple class diagrams but complete with sub-classes organized it per component (package in Java) => Jackpot!

Few more advises:

Eliminate deprecated classes
Find a symbol to mark a class is thread-safe (put a TS or something)
You could omit the least-used sub-classes (maybe) as you go along with your adventure

An example of a simple class diagram:

Compare to this (not-so-simple):

http://www.owlnet.rice.edu/~comp212/08-spring/lectures/30/reader.png

Hope that helps.