в 16:40, 26 мая 2010

2010-05-26T16:40:06Z

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2010-05-26T12:45:00Z

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==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>

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в 16:40, 26 мая 2010

Admin: 1 версия