C# stop and continue

Question

I need some way to do the following efficiently in C#:

Make program execution stop until certain value is changed.

Note: I do not want to make it with a while loop to avoid wasting cpu power..

Edit: And I want it to respond as quickly as possible after value has changed..

Edit: This will be inside my class method that is called by another code, however the value to be checked is inside my class... The method is supposed to wait until others code evaluate and change my value.. then it must continue to do its work.. unfortunately this is done many times(so I need to care for performance)

Answer 1

Monitor.Wait and Monitor.Pulse