Throw and Throw ex in C#

Throw preserves the stack trace. So lets say Source1 throws Error1 , its caught by Source2 and Source2 says throw then Source1 Error + Source2 Error will be available in the stack trace.

Throw ex does not preserve the stack trace. So all errors of Source1 will be wiped out and only Source2 error will sent to the client.

Sometimes just reading things are not clear , would suggest to watch this video demo to get more clarity , Throw vs Throw ex in C#.