23.3 How exceptions are handled

Exceptions are handled by a try statement (§15.10).
When an exception occurs, the system searches for the nearest catch clause
that can handle the exception,
as determined by the run-time type of the exception. First, the current
method is searched for a lexically
enclosing try statement, and the associated catch clauses of the try
statement are considered in order. If
that fails, the method that called the current method is searched for a
lexically enclosing try statement that
encloses the point of the call to the current method. This search continues
until a catch clause is found that
can handle the current exception, by naming an exception class that is of
the same class, or a base class, of
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the run-time type of the exception being thrown. A catch clause that
doesn?t name an exception class can
handle any exception.
Once a matching catch clause is found, the system prepares to transfer
control to the first statement of the
catch clause. Before execution of the catch clause begins, the system first
executes, in order any
finally clauses that were associated with try statements more nested that
than the one that caught the
exception.
If no matching catch clause is found, one of two things occurs:
? If the search for a matching catch clause reaches a static constructor (§1
7.11) or static field initializer,
then a System.TypeInitializationException is thrown at the point that
triggered the invocation
of the static constructor. The inner exception of the
System.TypeInitializationException
contains the exception that was originally thrown.
? If the search for matching catch clauses reaches the code that initially
started the thread, then execution
of the thread is terminated. The impact of such termination is
implementation-defined.
Exceptions that occur during destructor execution are worth special
mention. If an exception occurs during
destructor execution, and that exception is not caught, then the execution
of that destructor is terminated and
the destructor of the base class (if any) is called. If there is no base
class (as in the case of the object type)
or if there is no base class destructor, then the exception is discarded.