How to show If else condition in a UML system sequence diagram

Question

Is it possible to describe an if-else structure in a system sequence diagram? If yes, how is this done?

Answer 1

Here's more info about combined fragments from the VS 2010 sequence diagram documentation:

• UML Sequence Diagrams: Reference
• UML Sequence Diagrams: Guidelines
• Describing Control Flow with Fragments in UML Sequence Diagrams