Exception in VB.NET
In this article we will discuss about the Exception.
Exception:
Exception is an event, that effect the normal flow of code during the program execution. Exception is divided in to two parts:
-
System define Exceptions
-
User define Exception
System Define Exception:
These Exceptions are created by the Microsoft and are considered to be part of the .NET Framework and FCL. by the convention ,system define Exception Inherit from the System Exception class. There are various type of system Exceptions that are:
-
NullReferance Exception
-
InvalidCast Exception
-
IndexOutofRange Exception
-
Invalid Exception
-
TypeLoad Exception
-
ExecutionEngine Exception
-
OutOfMemory Exception
-
StackOverFlow Exception
-
Arithmetic Exception
-
OverFlow Exception
-
DividebyZero Exception
-
NotFiniteNumber Exception
-
Argument Exception
-
ArgumentNull Exception
-
ArgumentOutOfRange Exception
User Define Exception:
Some times you need to report an error condition that does not map to an existing system define exception classes. In such case you can design a custom exception class for creating and throwing user defined exceptions by creating a new class that Inherit from Application Exception class.
Exception Handling:
In .NET Framework Exception handling is done by the three blocks. That are:
-
Try
-
Throws
-
Catch or Finally
Try Block:
A Try Statement allow you to perform operations and to call other method within a try block. the try block is often referred to as a guarded block because it give the CLR an associated backup plan for what to do when things go wrong.
Module Module1
Sub Main()
Try
Dim x As Integer
Dim y As Integer
x = 123
y = x / 0
Catch ex As Exception
Console.WriteLine("DividebyZero Exception")
End Try
End Sub
End Module
Throws Black:
Throwing an exception is the one an only official way to report an error condition to the .NET Framework. if you call a method and it does not throw an exception, you can assume that the method was able to do what you expected it to do.
Catch Block:
In Catch Block, it can hold the exception event that are occur during program execution time.
Catch ex As Exception
Coding for System Define Exception Handling:
Module Module1
Class over
Dim value As Integer = 980000000
Public Sub voer1()
Try
' Square the original value.
Dim square As Integer = value * value
Console.WriteLine(value, square)
Catch e As OverflowException
Dim square As Double = Math.Pow(value, 5)
Console.WriteLine("Exception", _
square, Int32.MaxValue)
End Try
End Sub
End Class
Sub Main()
Dim obj As New over
obj.voer1()
End Sub
End Module
Output: