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SerializationException Constructor (SerializationInfo, StreamingContext)

Initializes a new instance of the SerializationException class from serialized data.

Namespace:  System.Runtime.Serialization
Assembly:  mscorlib (in mscorlib.dll)

'Declaration
Protected Sub New ( _
	info As SerializationInfo, _
	context As StreamingContext _
)

Parameters

info
Type: System.Runtime.Serialization.SerializationInfo
The serialization information object holding the serialized object data in the name-value form.
context
Type: System.Runtime.Serialization.StreamingContext
The contextual information about the source or destination of the exception.

ExceptionCondition
ArgumentNullException

The info parameter is Nothing.

The current constructor is called during deserialization to reconstitute the exception object transmitted over a stream. (For more information on serialization see [<topic://cpconSerialization>].)


Imports System
Imports System.IO
Imports System.Collections
Imports System.Runtime.Serialization.Formatters.Binary
Imports System.Runtime.Serialization
Imports System.Runtime.InteropServices
Imports System.Security.Permissions

<Assembly: SecurityPermission( _
SecurityAction.RequestMinimum, Execution:=True)> 
' This class includes several Win32 interop definitions.
Friend Class Win32
    Public Shared ReadOnly InvalidHandleValue As New IntPtr(-1)
    Public Const FILE_MAP_WRITE As Int32 = 2
    Public Const PAGE_READWRITE As Int32 = &H4

    <DllImport("Kernel32", CharSet:=CharSet.Unicode)> _
    Public Shared Function CreateFileMapping(ByVal hFile As IntPtr, _
                                             ByVal pAttributes As IntPtr, _
                                             ByVal flProtect As Int32, _
                                             ByVal dwMaximumSizeHigh As Int32, _
                                             ByVal dwMaximumSizeLow As Int32, _
                                             ByVal pName As String) As IntPtr
    End Function

    <DllImport("Kernel32", CharSet:=CharSet.Unicode)> _
    Public Shared Function OpenFileMapping(ByVal dwDesiredAccess As Int32, _
                                           ByVal bInheritHandle As Boolean, _
                                           ByVal name As String) As IntPtr
    End Function

    <DllImport("Kernel32", CharSet:=CharSet.Unicode)> _
    Public Shared Function CloseHandle(ByVal handle As IntPtr) As Boolean
    End Function

    <DllImport("Kernel32", CharSet:=CharSet.Unicode)> _
    Public Shared Function MapViewOfFile(ByVal hFileMappingObject As IntPtr, _
                                         ByVal dwDesiredAccess As Int32, _
                                         ByVal dwFileOffsetHigh As Int32, _
                                         ByVal dwFileOffsetLow As Int32, _
                                         ByVal dwNumberOfBytesToMap As IntPtr) _
                                         As IntPtr
    End Function

    <DllImport("Kernel32", CharSet:=CharSet.Unicode)> _
    Public Shared Function UnmapViewOfFile(ByVal address As IntPtr) As Boolean
    End Function

    <DllImport("Kernel32", CharSet:=CharSet.Unicode)> _
    Public Shared Function DuplicateHandle(ByVal hSourceProcessHandle As IntPtr, _
                                           ByVal hSourceHandle As IntPtr, _
                                           ByVal hTargetProcessHandle As IntPtr, _
                                           ByRef lpTargetHandle As IntPtr, _
                                           ByVal dwDesiredAccess As Int32, _
                                           ByVal bInheritHandle As Boolean, _
                                           ByVal dwOptions As Int32) As Boolean
    End Function

    Public Const DUPLICATE_CLOSE_SOURCE As Int32 = &H1
    Public Const DUPLICATE_SAME_ACCESS As Int32 = &H2

    <DllImport("Kernel32", CharSet:=CharSet.Unicode)> Public Shared Function GetCurrentProcess() As IntPtr
    End Function
End Class


' This class wraps memory that can be simultaneously 
' shared by multiple AppDomains and Processes.
<Serializable()> Public NotInheritable Class SharedMemory
    Implements ISerializable
    Implements IDisposable

    ' The handle and string that identify 
    ' the Windows file-mapping object.
    Private m_hFileMap As IntPtr = IntPtr.Zero
    Private m_name As String

    ' The address of the memory-mapped file-mapping object.
    Private m_address As IntPtr
    <SecurityPermissionAttribute(SecurityAction.LinkDemand, _
    Flags:=SecurityPermissionFlag.UnmanagedCode)> _
    Public Function GetByte(ByVal offset As Int32) As Byte
        Dim b(0) As Byte
        Marshal.Copy(New IntPtr(m_address.ToInt64() + offset), b, 0, 1)
        Return b(0)
    End Function

    <SecurityPermissionAttribute(SecurityAction.LinkDemand, _
    Flags:=SecurityPermissionFlag.UnmanagedCode)> _
    Public Sub SetByte(ByVal offset As Int32, ByVal value As Byte)
        Dim b(0) As Byte
        b(0) = value
        Marshal.Copy(b, 0, New IntPtr(m_address.ToInt64() + offset), 1)
    End Sub


    ' The constructors.
    Public Sub New(ByVal size As Int32)
        Me.New(size, Nothing)
    End Sub

    Public Sub New(ByVal size As Int32, ByVal name As String)
        m_hFileMap = Win32.CreateFileMapping(Win32.InvalidHandleValue, _
           IntPtr.Zero, Win32.PAGE_READWRITE, 0, size, name)
        If (m_hFileMap.Equals(IntPtr.Zero)) Then _
           Throw New Exception("Could not create memory-mapped file.")
        m_name = name
        m_address = Win32.MapViewOfFile(m_hFileMap, _
           Win32.FILE_MAP_WRITE, 0, 0, IntPtr.Zero)
    End Sub


    ' The cleanup methods.
    Public Sub Dispose() Implements IDisposable.Dispose
        GC.SuppressFinalize(Me)
        Dispose(True)
    End Sub

    Private Sub Dispose(ByVal disposing As Boolean)
        Win32.UnmapViewOfFile(m_address)
        Win32.CloseHandle(m_hFileMap)
        m_address = IntPtr.Zero
        m_hFileMap = IntPtr.Zero
    End Sub

    Protected Overrides Sub Finalize()
        Dispose(False)
    End Sub


    ' Private helper methods.
    Private Shared Function AllFlagsSet(ByVal flags As Int32, _
                                        ByVal flagsToTest As Int32) As Boolean
        Return (flags And flagsToTest) = flagsToTest
    End Function

    Private Shared Function AnyFlagsSet(ByVal flags As Int32, _
                                        ByVal flagsToTest As Int32) As Boolean
        Return (flags And flagsToTest) <> 0
    End Function


    ' The security attribute demands that code that calls  
    ' this method have permission to perform serialization.
    <SecurityPermissionAttribute(SecurityAction.Demand, SerializationFormatter:=True)> _
    Sub GetObjectData(ByVal info As SerializationInfo, _
                      ByVal context As StreamingContext) _
                      Implements ISerializable.GetObjectData
        ' The context's State member indicates where the object will be deserialized.

        ' A SharedMemory object cannot be serialized 
        ' to any of the following destinations.
        Const InvalidDestinations As StreamingContextStates = _
           StreamingContextStates.CrossMachine Or _
           StreamingContextStates.File Or _
           StreamingContextStates.Other Or _
           StreamingContextStates.Persistence Or _
           StreamingContextStates.Remoting
        If AnyFlagsSet(CType(context.State, Int32), _
                       CType(InvalidDestinations, Int32)) Then
            Throw New SerializationException("The SharedMemory object " & _
               "cannot be serialized to any of the following streaming contexts: " _
               & InvalidDestinations)
        End If

        Const DeserializableByHandle As StreamingContextStates = _
                 StreamingContextStates.Clone Or _
                 StreamingContextStates.CrossAppDomain

        If AnyFlagsSet(CType(context.State, Int32), _
              CType(DeserializableByHandle, Int32)) Then
            info.AddValue("hFileMap", m_hFileMap)
        End If

        Const DeserializableByName As StreamingContextStates = _
                 StreamingContextStates.CrossProcess   ' The same computer.
        If AnyFlagsSet(CType(context.State, Int32), CType(DeserializableByName, _
                       Int32)) Then
            If m_name = Nothing Then
                Throw New SerializationException("The SharedMemory object " & _
                   "cannot be serialized CrossProcess because it was not constructed " & _
                   "with a String name.")
            End If
            info.AddValue("name", m_name)
        End If
    End Sub

    Private Sub New(ByVal info As SerializationInfo, ByVal context As StreamingContext)
        ' The context's State member indicates where the object was serialized from.

        Const InvalidSources As StreamingContextStates = _
                 StreamingContextStates.CrossMachine Or _
                 StreamingContextStates.File Or _
                 StreamingContextStates.Other Or _
                 StreamingContextStates.Persistence Or _
                 StreamingContextStates.Remoting

        If AnyFlagsSet(CType(context.State, Int32), CType(InvalidSources, Int32)) Then
            Throw New SerializationException("The SharedMemory object " & _
               "cannot be deserialized from any of the following stream contexts: " & _
               InvalidSources)
        End If

        Const SerializedByHandle As StreamingContextStates = _
                 StreamingContextStates.Clone Or _
                 StreamingContextStates.CrossAppDomain ' The same process.
        If AnyFlagsSet(CType(context.State, Int32), _
              CType(SerializedByHandle, Int32)) Then
            Try
                Win32.DuplicateHandle(Win32.GetCurrentProcess(), _
                   CType(info.GetValue("hFileMap", GetType(IntPtr)), IntPtr), _
                      Win32.GetCurrentProcess(), m_hFileMap, 0, False, _
                      Win32.DUPLICATE_SAME_ACCESS)
            Catch e As SerializationException
                Throw New SerializationException("A SharedMemory was not " & _
                   "serialized using any of the following streaming contexts: " & _
                   SerializedByHandle)
            End Try
        End If

        Const SerializedByName As StreamingContextStates = _
                 StreamingContextStates.CrossProcess   ' The same computer.
        If AnyFlagsSet(CType(context.State, Int32), _
                       CType(SerializedByName, Int32)) Then
            Try
                m_name = info.GetString("name")
            Catch e As SerializationException
                Throw New SerializationException("A SharedMemory object " & _
                   "was not serialized using any of the following streaming contexts: " & _
                   SerializedByName)
            End Try
            m_hFileMap = Win32.OpenFileMapping(Win32.FILE_MAP_WRITE, False, m_name)
        End If
        If Not m_hFileMap.Equals(IntPtr.Zero) Then
            m_address = Win32.MapViewOfFile(m_hFileMap, _
               Win32.FILE_MAP_WRITE, 0, 0, IntPtr.Zero)
        Else
            Throw New SerializationException("A SharedMemory object " & _
               "could not be deserialized.")
        End If
    End Sub
End Class

Class App
    <STAThread()> Shared Sub Main()
        Serialize()
        Console.WriteLine()
        Deserialize()
    End Sub

    Shared Sub Serialize()
        ' Create a hashtable of values that will eventually be serialized.
        Dim sm As New SharedMemory(1024, "MyMemory")
        Dim x As Int32
        For x = 0 To 99
            sm.SetByte(x, x)
        Next

        Dim b(9) As Byte
        For x = 0 To b.Length - 1
            b(x) = sm.GetByte(x)
        Next
        Console.WriteLine(BitConverter.ToString(b))

        ' To serialize the hashtable (and its key/value pairs), you must first 
        ' open a stream for writing. Use a file stream here.
        Dim fs As New FileStream("DataFile.dat", FileMode.Create)

        ' Construct a BinaryFormatter telling it where 
        ' the objects will be serialized to.
        Dim formatter As New BinaryFormatter(Nothing, _
           New StreamingContext(StreamingContextStates.CrossAppDomain))
        Try
            formatter.Serialize(fs, sm)
        Catch e As SerializationException
            Console.WriteLine("Failed to serialize. Reason: " + e.Message)
            Throw
        Finally
            fs.Close()
        End Try
    End Sub

    Shared Sub Deserialize()
        ' Declare the hashtable reference.
        Dim sm As SharedMemory = Nothing

        ' Open the file containing the data that you want to deserialize.
        Dim fs As New FileStream("DataFile.dat", FileMode.Open)
        Try
            Dim Formatter As New BinaryFormatter(Nothing, _
               New StreamingContext(StreamingContextStates.CrossAppDomain))

            ' Deserialize the SharedMemory object from the file and 
            ' assign the reference to the local variable.
            sm = DirectCast(Formatter.Deserialize(fs), SharedMemory)
        Catch e As SerializationException
            Console.WriteLine("Failed to deserialize. Reason: " & e.Message)
        Finally
            fs.Close()
        End Try

        ' To prove that the SharedMemory object deserialized correctly, 
        ' display some of its bytes to the console.
        Dim b(9) As Byte
        Dim x As Int32
        For x = 0 To b.Length - 1
            b(x) = sm.GetByte(x)
        Next
        Console.WriteLine(BitConverter.ToString(b))
    End Sub
End Class


.NET Framework

Supported in: 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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