I have a workflow that is created in code and a variable of type CorrelationHandle gets initialized in one of the activities. now this variable is passed around to other custom activities. In one of those activities i need to call some other service with correlation handler's value (which is a guid).
Is there any way to get the handle's value from with in an activity where the handle is passed into the activity as an InArgument ?
A CorrelationHandle is something that is used internally by the WF4 runtime. There is nothing you can do with other than pass it around.
It appears you are interested in value associated with the CorrelationHandle to correlate incoming messages. That is a value the client passes to you, or you return, with the initial request. That values is also passed to you because it is part of the request. But there is nothing you can do to update an existing CorrelationHandle to anew value.