Exceptions - Illustrated C# 2005 - page 275

Searching Further
If the exception was raised in a section of code that was not guarded by a try statement, or if
the try statement did not have a matching exception handler—the system will have to look
further for a matching handler. It will do this by searching down the call stack, in sequence, to
see whether there is an enclosing try block with a matching handler.
Figure 11-7 illustrates the search process. On the left of the figure is the calling structure
of the code, and on the right is the call stack. The figure shows that Method2 is called from inside
the try block of Method1 . If an exception occurs inside the try block of Method2 , the system per-
forms the following steps:

First, the system checks to see whether Method2 was called from an enclosing try
statement.
-If so, Method2 's catch clauses are checked to see whether any of them match the
exception.

￿

If not, the system continues down the call stack to Method1 , searching for an
appropriate handler.

-

￿ f Method1 has an appropriate catch clause
- The system goes back to the top of the call stack—which is Method2 .

The system executes Method2 's finally block, and pops Method2 off the stack. -

It then executes Method1 's catch clause and its finally block. -

￿ f Method1 does not have an appropriate catch clause, it will continue searching down
the call stack.

Figure 11-7. Searching down the call stack