VB.Net/Development/Exception Yours

A user-defined exception class

<source lang="vbnet"> Imports System Public Class MainClass

  Shared Sub Main()
     " catch any NegativeNumberException thrown
     Try
        Throw New NegativeNumberException("Exception occurred")
         
     Catch formatException As FormatException
        Console.WriteLine(formatException.Message)
        " diplay MessageBox if negative number input
     Catch negativeNumberException As _
        NegativeNumberException
        Console.WriteLine(negativeNumberException.Message)
     End Try
  End Sub " Main

End Class Public Class NegativeNumberException

  Inherits ApplicationException
  Public Sub New()
     MyBase.New("Illegal operation for a negative number")
  End Sub " New
  " constructor for customizing error message
  Public Sub New(ByVal messageValue As String)
     MyBase.New(messageValue)
  End Sub " New
  " constructor for customizing error message and specifying
  " inner exception object
  Public Sub New(ByVal messageValue As String, _
     ByVal inner As Exception)
     MyBase.New(messageValue, inner)
  End Sub

End Class

      </source>

Define and Use your own Exception Class

<source lang="vbnet"> Imports System Public Class MainClass

   Shared Sub Main(ByVal args As String())
            Try
                Console.WriteLine("Open file here")
                Dim a As Double = 0
                Dim b As Double = 5
                Console.WriteLine("{0} / {1} = {2}", a, b, DoDivide(a, b))
                Console.WriteLine("This line may or may not print")
                " most derived exception type first
            Catch e As System.DivideByZeroException
                Console.WriteLine( _
                   "DivideByZeroException! Msg: {0}", e.Message)
                Console.WriteLine("HelpLink: {0}", e.HelpLink)
                " catch custom exception
            Catch e As MyCustomException
                Console.WriteLine( _
                   "MyCustomException! Msg: {0}", e.Message)
                Console.WriteLine("HelpLink: {0}", e.HelpLink)
            Catch " catch any uncaught exceptions
                Console.WriteLine("Unknown exception caught")
            Finally
                Console.WriteLine("Close file here.")
            End Try
   End Sub
        " do the division if legal
        Shared Public Function DoDivide( _
            ByVal a As Double, ByVal b As Double) As Double
            If b = 0 Then
                Dim e As New DivideByZeroException( )
                e.HelpLink = "http://www.vbex.ru"
                Throw e
            End If
            If a = 0 Then
                " create a custom exception instance
                Dim e As New _
                  MyCustomException("Can"t have zero divisor")
                e.HelpLink = _
                   "http://www.vbex.ru"
                Throw e
            End If
            Return a / b
        End Function "DoDivide

End Class

    Public Class MyCustomException
        Inherits System.ApplicationException
        Public Sub New(ByVal message As String)
            " pass the message up to the base class
            MyBase.New(message)
        End Sub "New
    End Class "MyCustomException
          
      </source>

Your own Exception Class

<source lang="vbnet"> Imports System Imports System.Text Imports System.Text.RegularExpressions

Public Class MainClass

        Shared Sub Main(  )
            Try
                Console.WriteLine("Open file here")
                Dim a As Double = 0
                Dim b As Double = 5
                Console.WriteLine("{0} / {1} = {2}", a, b, DoDivide(a, b))
                Console.WriteLine("This line may or may not print")
            " most derived exception type first
            Catch e As System.DivideByZeroException
                Console.WriteLine( _
                   "DivideByZeroException! Msg: {0}", e.Message)
                Console.WriteLine("HelpLink: {0}", e.HelpLink)
            " catch custom exception
            Catch e As MyCustomException
                Console.WriteLine( _
                   "MyCustomException! Msg: {0}", e.Message)
                Console.WriteLine("HelpLink: {0}", e.HelpLink)
            Catch " catch any uncaught exceptions
                Console.WriteLine("Unknown exception caught")
            Finally
                Console.WriteLine("Close file here.")
            End Try
        End Sub "Main
        Shared Public Function DoDivide(ByVal a As Double, ByVal b As Double) As Double
            If b = 0 Then
                Throw New System.DivideByZeroException(  )
            End If
            If a = 0 Then
                Throw New System.ArithmeticException(  )
            End If
            Return a / b
        End Function
  

End Class

    Public Class MyCustomException
        Inherits System.ApplicationException
        Public Sub New(ByVal message As String)
            MyBase.New(message)
        End Sub
    End Class
          
      </source>

Your own Object Expired Exception

<source lang="vbnet"> Imports System Imports System.Collections Public Class MainClass

   Shared Sub Main(ByVal args As String())
       Try
           Throw New ObjectExpiredException("This object has expired.")
       Catch ex As Exception
           Console.WriteLine(ex.Message)
       End Try
   End Sub

End Class Public Class ObjectExpiredException

   Inherits System.ApplicationException
   " No parameters. Use a default message.
   Public Sub New()
       MyBase.New("This object has expired")
   End Sub
   " Set the message.
   Public Sub New(ByVal new_message As String)
       MyBase.New(new_message)
   End Sub
   " Set the message and inner exception.
   Public Sub New(ByVal new_message As String, ByVal inner_exception As Exception)
       MyBase.New(new_message, inner_exception)
   End Sub

End Class

      </source>