Exceptions in C# provide a structured, uniform, and type-safe way of handling both system level and application-level error conditions. [Note: The exception mechanism is C# is quite similar to that of C++, with a few important differences:

• In C#, all exceptions must be represented by an instance of a class type derived from System.Exception. In C++, any value of any type can be used to represent an exception.
• In C#, a finally block (15.10) can be used to write termination code that executes in both normal execution and exceptional conditions. Such code is difficult to write in C++ without duplicating code.
• In C#, system-level exceptions such as overflow, divide-by-zero, and null dereferences have well defined exception classes and are on a par with application-level error conditions. end note]

In This Section:

• 23.1: Causes of exceptions
• 23.2: The System.Exception class
• 23.3: How exceptions are handled
• 23.4: Common Exception Classes