| We must
be able to pause execution of our application
to debug it effectively. We use breakpoints
most of the time to tell the debugger
where to stop.
We usually want the debugger to pause
when our application throws an exception.
The debugger breaks on an exception
by default unless our code catches
that exception. In other words, the
debugger will not stop if the line
that throws the exception is wrapped
in a Try/Catch block. Execution continues
and we may be unable to discover where
or even if the exception was thrown.
We can configure the Visual Studio
debugger to break whenever an exception
is thrown, even if it is caught in
a Try/Catch block. Press Ctrl-Alt-
E; Visual Studio presents the Exceptions dialog. The dialog displays a tree
of exceptions, categorized by general
type.
Each exception (or exception type)
is paired with two checkbox columns.
The column titled "Thrown" is
unchecked by default; if checked, the
debugger should pause whenever the
exception is thrown. The second, "User-unhandled",
is typically checked and tells the
debugger to pause if the exception
is not handled (e.g., is not caught
in a Try/Catch block).
We can tell the debugger to break
on a broad category of exceptions (such
as break on all Common Language Runtime
Exceptions), or a category of exceptions
from a namespace (such as any System.IO
exception), or on a specific exception
(like System.IO.IOException) by checking
the "Thrown" checkbox as
shown in Figure 1.
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