' Example for the Exception( SerializationInfo, StreamingContext )
' constructor and the Exception.GetObjectData( SerializationInfo,
' StreamingContext ) method.
'
' If compiling with the Visual Basic compiler (VBC) from the command
' prompt, be sure to add the following switch:
' /reference:System.Runtime.Serialization.Formatters.Soap.dll
Imports System
Imports System.IO
Imports System.Runtime.Serialization
Imports System.Runtime.Serialization.Formatters.Soap
Imports Microsoft.VisualBasic
Imports System.Security.Permissions
Namespace NDP_UE_VB
' Define a serializable derived exception class.
<Serializable()> _
Class SecondLevelException
Inherits Exception
' This public constructor is used by class instantiators.
Public Sub New( message As String, inner As Exception )
MyBase.New( message, inner )
HelpLink = "http://MSDN.Microsoft.com"
Source = "Exception_Class_Samples"
End Sub ' New
' This protected constructor is used for deserialization.
Protected Sub New( info As SerializationInfo, _
context As StreamingContext )
MyBase.New( info, context )
End Sub ' New
' GetObjectData performs a custom serialization.
<SecurityPermissionAttribute(SecurityAction.Demand, _
SerializationFormatter:=True)> _
Overrides Sub GetObjectData( info As SerializationInfo, _
context As StreamingContext)
' Change the case of two properties, and then use the
' method of the base class.
HelpLink = HelpLink.ToLower()
Source = Source.ToUpper()
MyBase.GetObjectData(info, context)
End Sub ' ISerializable.GetObjectData
End Class ' SecondLevelException
Module SerializationDemo
Sub Main()
Console.WriteLine( _
"This example of the Exception constructor " & _
"and Exception.GetObjectData " & vbCrLf & _
"with SerializationInfo and StreamingContext " & _
"parameters generates " & vbCrLf & _
"the following output." & vbCrLf )
' This code forces a division by 0 and catches the
' resulting exception.
Try
Try
Dim zero As Integer = 0
Dim ecks As Integer = 1 \ zero
' Create a new exception to throw again.
Catch ex As Exception
Dim newExcept As New SecondLevelException( _
"Forced a division by 0 and threw " & _
"another exception.", ex )
Console.WriteLine( _
"Forced a division by 0, caught the " & _
"resulting exception, " & vbCrLf & _
"and created a derived exception:" & vbCrLf )
Console.WriteLine( "HelpLink: {0}", _
newExcept.HelpLink )
Console.WriteLine( "Source: {0}", _
newExcept.Source )
' This FileStream is used for the serialization.
Dim stream As New FileStream( _
"NewException.dat", FileMode.Create )
' Serialize the derived exception.
Try
Dim formatter As New SoapFormatter( Nothing, _
New StreamingContext( _
StreamingContextStates.File ) )
formatter.Serialize( stream, newExcept )
' Rewind the stream and deserialize the
' exception.
stream.Position = 0
Dim deserExcept As SecondLevelException = _
CType( formatter.Deserialize( stream ), _
SecondLevelException )
Console.WriteLine( vbCrLf & _
"Serialized the exception, and then " & _
"deserialized the resulting stream " & _
"into a " & vbCrLf & "new exception. " & _
"The deserialization changed the case " & _
"of certain properties:" & vbCrLf )
' Throw the deserialized exception again.
Throw deserExcept
Catch se As SerializationException
Console.WriteLine( "Failed to serialize: {0}", _
se.ToString( ) )
Finally
stream.Close( )
End Try
End Try
Catch ex As Exception
Console.WriteLine( "HelpLink: {0}", ex.HelpLink )
Console.WriteLine( "Source: {0}", ex.Source )
Console.WriteLine( )
Console.WriteLine( ex.ToString( ) )
End Try
End Sub ' Main
End Module ' SerializationDemo
End Namespace ' NDP_UE_VB
' This example of the Exception constructor and Exception.GetObjectData
' with SerializationInfo and StreamingContext parameters generates
' the following output.
'
' Forced a division by 0, caught the resulting exception,
' and created a derived exception:
'
' HelpLink: http://MSDN.Microsoft.com
' Source: Exception_Class_Samples
'
' Serialized the exception, and then deserialized the resulting stream into a
' new exception. The deserialization changed the case of certain properties:
'
' HelpLink: http://msdn.microsoft.com
' Source: EXCEPTION_CLASS_SAMPLES
'
' NDP_UE_VB.SecondLevelException: Forced a division by 0 and threw another exce
' ption. ---> System.DivideByZeroException: Attempted to divide by zero.
' at NDP_UE_VB.SerializationDemo.Main()
' --- End of inner exception stack trace ---
' at NDP_UE_VB.SerializationDemo.Main()