Exception in .Net Framework

Exception Types

There are a number of exception classes provided by C#, all of which inherit
from the System.Exception class. Following are some common exception classes.

SystemException

A failed run-time check;used as a base class for other.

AccessException

Failure to access a type member, such as a method or field.

ArgumentException

An argument to a method was invalid.

ArgumentNullException

A null argument was passed to a method that doesn't accept it.

ArgumentOutOfRangeException

Argument value is out of range.

ArithmeticException

Arithmetic over - or underflow has occurred.

ArrayTypeMismatchException

Attempt to store the wrong type of object in an array.

BadImageFormatException

Image is in the wrong format.

CoreException

Base class for exceptions thrown by the runtime.

DivideByZeroException

An attempt was made to divide by zero.

FormatException

The format of an argument is wrong.

IndexOutOfRangeException

An array index is out of bounds.

InvalidCastExpression

An attempt was made to cast to an invalid class.

InvalidOperationException

A method was called at an invalid time.

MissingMemberException

An invalid version of a DLL was accessed.

NotFiniteNumberException

A number is not valid.

NotSupportedException

Indicates that a method is not implemented by a class.

NullReferenceException

Attempt to use an unassigned reference.

OutOfMemoryException

Not enough memory to continue execution.

StackOverflowException

A stack has overflown.

The finally block is used to do all the clean up code. It does not support
the error message, but all the code contained in the finally block is executed
after the exception is raised. We can use this block along with try-catch and
only with catch too.

The finally block is executed even if the error is raised. Control is always
passed to the finally block regardless of how the try blocks exits.

This is shown in the following example:

int a, b = 0 ;
Console.WriteLine( "My program starts" ) ;
try
{
a = 10 / b;
}
catch ( InvalidOperationException e )
{
Console.WriteLine ( e ) ;
}
catch ( DivideByZeroException e)
{
Console.WriteLine ( e ) ;
}
finally
{
Console.WriteLine ( "finally" ) ;
}
Console.WriteLine ( "Remaining program" ) ;

The output here is:

My program starts

System.DivideByZeroException: Attempted to divide by zero.

at ConsoleApplication4.Class1.Main(String[] args) in d:\programs\consoleapplication4\class1.cs:line
51

finally

Remaining program

But then what's the difference? We could have written

Console.WriteLine ("finally");

after the catch block, and not write the finally block at all. Writing finally
did not make much of a difference. Anyway the code written after catch gets executed.
The answer to this is not clear in this program. It will be clear when we see
the try-finally and the throw statement.