What is the yield keyword used for in C#?

Answer 1

Recently Raymond Chen also ran an interesting series of articles on the yield keyword.

• The implementation of iterators in C# and its consequences (part 1)
• The implementation of iterators in C# and its consequences (part 2)
• The implementation of iterators in C# and its consequences (part 3)
• The implementation of iterators in C# and its consequences (part 4)

While it's nominally used for easily implementing an iterator pattern, but can be generalized into a state machine. No point in quoting Raymond, the last part also links to other uses (but the example in Entin's blog is esp good, showing how to write async safe code).