How do Linq Expressions determine equality?

Question

I am considering using a Linq Expression as a key in a dictionary. However, I am concerned that I will get strange results, because I don\'t know how Equality is determined

Answer 1

Your test compares expressions. Expressions themselves offer only reference equality; your test will probably show "false". To cheek for semantic equality you would need to do a lot of work, for example - are:

x => 123

And

y => 123

Equivalent? As a crude test you can compare ToString(), but this will be exceptionally brittle.