Exception Handling In VB.NET

What is Exception Handling?

Explanation

Exception Handling in vb.net 2008.

Exceptions Handling are errors that are triggered at runtime, that are handled in VB.net using structured error handling with the Try..Catch..Finally statement. The On erro goto, On Error Resume Next statement is used for unstructured error handling.
The exceptions can be handled in the Try..Catch..finally using the Built-in exception handling methods.

Example1:

Module Module1
Sub Main()
Dim a(3) As Integer
Try
a(5) = 45
Catch ex As IndexOutOfRangeException
Console.WriteLine(ex.Message)
Catch ex As Exception
Console.WriteLine(ex.Message)
Finally
Console.WriteLine("End of Execution")
End Try
Console.Read()
End Sub
End Module

Result:

Index was outside the bounds of the array
End of Execution

Description:

In the above example, the dimension of the array declared is '3' and the array given array under the Try statement is '5'. The exception is caught by the catch statement using the specific exception option IndexOutOfRangeException and even the Exception option display messages for all exceptions.

On Error Goto Statement:

Example2:

Module Module1
Sub Main()
Dim i, j As Integer
For i = 0 To 10 Step 1
On Error GoTo ErrorHandler
j = 100 / i
Console.WriteLine("Value of j is::")
Console.WriteLine(j)
Next
ErrorHandler:
Console.WriteLine("Division by zero error")
Console.Read()
End Sub
End Module

Result:

Division by zero error

On Error Goto Statement:

In the above example the ustructured error handling statement On Error Goto is used along with the ErrorHandler to display the error message that diverts the flow of the program itself.

Example3:

Module Module1
Public Class student
Public Function Add(ByVal i As Integer,
ByVal j As Integer) As Integer
Console.WriteLine("Result:"(i / j))
End Function
End Class
Sub Main()
On Error Resume Next
Dim obj As New student
obj.Add(10, 0)
Console.WriteLine("Check the Arguments")
Console.Read()
End Sub
End Module