how can CLR handle Exceptions

Basically, an exception object is an instance of some class which is thrown to when something exceptional goes wrong, e.g. a file I/O operation problem when a file is locked. The use of object types that inherit from System.Exception is actually not a direct requirement of the CLR. Essentially, exceptions are thrown when the current piece of code can't deal with the problematic situation and wants the caller to handle it further on. In order to handle such exceptions, a block of code must be protected which results in a so-called "protected block".