VB.NET CryptographicException類代碼示例

' 導入命名空間
Imports System.Text
Imports System.Security.Cryptography
Imports System.Runtime.Serialization

Public Class Form1
    Inherits System.Windows.Forms.Form

    ' Event handler for Run button.
    Private Sub Button1_Click( _
        ByVal sender As System.Object, _
        ByVal e As System.EventArgs) Handles Button1.Click

        tbxOutput.Cursor = Cursors.WaitCursor
        tbxOutput.Text = ""

        TestConstructors()
        ShowProperties()

        ' Reset the cursor and conclude application.
        tbxOutput.AppendText(vbCrLf + "This sample completed " + _
            "successfully; Exit to continue.")
        tbxOutput.Cursor = Cursors.Default
    End Sub

    ' Test each public implementation of the CryptographicException
    ' constructors.
    Private Sub TestConstructors()
        EmptyConstructor()
        IntConstructor()
        StringConstructor()
        StringExceptionConstructor()
        StringStringConstructor()
    End Sub

    Private Sub EmptyConstructor()
        ' Construct a CryptographicException with no parameters.
        Dim cryptographicException As New CryptographicException
        WriteLine("Created an empty CryptographicException.")
    End Sub

    Private Sub IntConstructor()
        ' Construct a CryptographicException using the error code for an
        ' unexpected operation exception.
        Dim exceptionNumber As Integer = &H80131431
        Dim cryptographicException As _
            New CryptographicException(exceptionNumber)
        WriteLine("Created a CryptographicException with the " + _
            "following error code: " + exceptionNumber.ToString())
    End Sub

    Private Sub StringConstructor()
        ' Construct a CryptographicException using a custom error message.
        Dim errorMessage As String = "Unexpected Operation exception."
        Dim cryptographicException As New CryptographicException(errorMessage)
        WriteLine("Created a CryptographicException with the " + _
            "following error message: " + errorMessage)
    End Sub

    Private Sub StringExceptionConstructor()
        ' Construct a CryptographicException using a custom error message
        ' and an inner exception.
        Dim errorMessage As String = "The current operation is not supported."
        Dim nullException As New NullReferenceException
        Dim cryptographicException As _
            New CryptographicException(errorMessage, nullException)
        Write("Created a CryptographicException with the following error ")
        Write("message: " + errorMessage + " and the inner exception of ")
        WriteLine(nullException.ToString())
    End Sub

    Private Sub StringStringConstructor()
        ' Create a CryptographicException using a time format and a the 
        ' current date.
        Dim dateFormat As String = "{0:t}"
        Dim timeStamp As String = DateTime.Now.ToString()
        Dim cryptographicException As _
            New CryptographicException(dateFormat, timeStamp)
        Write("Created a CryptographicException with (" + dateFormat)
        WriteLine(") as the format and (" + timeStamp + ") as the message.")
    End Sub

    ' Construct an invalid DSACryptoServiceProvider to throw a
    ' CryptographicException for introspection.
    Private Sub ShowProperties()
        Try
            ' Create a DSACryptoServiceProvider with invalid provider type
            ' code to throw a CryptographicException exception.
            Dim cspParams As New CspParameters(44)
            Dim DSAalg As New DSACryptoServiceProvider(cspParams)
        Catch ex As CryptographicException
            ' Retrieve the link to the help file for the exception.
            Dim helpLink As String = ex.HelpLink

            ' Retrieve the exception that caused the current
            ' CryptographicException exception.
            Dim innerException As System.Exception = ex.InnerException
            Dim innerExceptionMessage As String = ""
            If (Not innerException Is Nothing) Then
                innerExceptionMessage = innerException.ToString()
            End If

            ' Retrieve the message that describes the exception.
            Dim message As String = ex.Message

            ' Retrieve the name of the application that caused the exception.
            Dim exceptionSource As String = ex.Source

            ' Retrieve the call stack at the time the exception occurred.
            Dim stackTrace As String = ex.StackTrace

            ' Retrieve the method that threw the exception.
            Dim targetSite As System.Reflection.MethodBase
            targetSite = ex.TargetSite
            Dim siteName As String = targetSite.Name

            ' Retrieve the entire exception as a single string.
            Dim entireException As String = ex.ToString()

            ' GetObjectData
            setSerializationInfo(ex)

            ' Get the root exception that caused the current
            ' CryptographicException exception.
            Dim baseException As System.Exception = ex.GetBaseException()
            Dim baseExceptionMessage As String = ""
            If (Not baseException Is Nothing) Then
                baseExceptionMessage = baseException.Message
            End If

            WriteLine("Caught an expected exception:")
            WriteLine(entireException)

            WriteLine(vbCrLf + "Properties of the exception are as follows:")
            WriteLine("Message: " + message)
            WriteLine("Source: " + exceptionSource)
            WriteLine("Stack trace: " + stackTrace)
            WriteLine("Help link: " + helpLink)
            WriteLine("Target site's name: " + siteName)
            WriteLine("Base exception message: " + baseExceptionMessage)
            WriteLine("Inner exception message: " + innerExceptionMessage)

        End Try
    End Sub

    Private Sub setSerializationInfo(ByRef ex As CryptographicException)
        ' Insert information about the exception into a serialized object.
        Dim formatConverter As New FormatterConverter
        Dim serializationInfo As _
            New SerializationInfo(ex.GetType(), formatConverter)
        Dim streamingContext As _
            New StreamingContext(StreamingContextStates.All)

        ex.GetObjectData(serializationInfo, streamingContext)
    End Sub

    ' Write specified message to the output textbox.
    Private Sub Write(ByVal message As String)
        tbxOutput.AppendText(message)
    End Sub

    ' Write specified message with a carriage return to the output textbox.
    Private Sub WriteLine(ByVal message As String)
        tbxOutput.AppendText(message + vbCrLf)
    End Sub

    ' Event handler for Exit button.
    Private Sub Button2_Click( _
        ByVal sender As System.Object, _
        ByVal e As System.EventArgs) Handles Button2.Click

        Application.Exit()
    End Sub
#Region " Windows Form Designer generated code "

    Public Sub New()
        MyBase.New()

        'This call is required by the Windows Form Designer.
        InitializeComponent()

        'Add any initialization after the InitializeComponent() call

    End Sub

    'Form overrides dispose to clean up the component list.
    Protected Overloads Overrides Sub Dispose(ByVal disposing As Boolean)
        If disposing Then
            If Not (components Is Nothing) Then
                components.Dispose()
            End If
        End If
        MyBase.Dispose(disposing)
    End Sub

    'Required by the Windows Form Designer
    Private components As System.ComponentModel.IContainer

    'NOTE: The following procedure is required by the Windows Form Designer
    'It can be modified using the Windows Form Designer.  
    'Do not modify it using the code editor.
    Friend WithEvents Panel2 As System.Windows.Forms.Panel
    Friend WithEvents Panel1 As System.Windows.Forms.Panel
    Friend WithEvents Button1 As System.Windows.Forms.Button
    Friend WithEvents Button2 As System.Windows.Forms.Button
    Friend WithEvents tbxOutput As System.Windows.Forms.RichTextBox
    <System.Diagnostics.DebuggerStepThrough()> _
    Private Sub InitializeComponent()
        Me.Panel2 = New System.Windows.Forms.Panel
        Me.Button1 = New System.Windows.Forms.Button
        Me.Button2 = New System.Windows.Forms.Button
        Me.Panel1 = New System.Windows.Forms.Panel
        Me.tbxOutput = New System.Windows.Forms.RichTextBox
        Me.Panel2.SuspendLayout()
        Me.Panel1.SuspendLayout()
        Me.SuspendLayout()
        '
        'Panel2
        '
        Me.Panel2.Controls.Add(Me.Button1)
        Me.Panel2.Controls.Add(Me.Button2)
        Me.Panel2.Dock = System.Windows.Forms.DockStyle.Bottom
        Me.Panel2.DockPadding.All = 20
        Me.Panel2.Location = New System.Drawing.Point(0, 320)
        Me.Panel2.Name = "Panel2"
        Me.Panel2.Size = New System.Drawing.Size(616, 64)
        Me.Panel2.TabIndex = 1
        '
        'Button1
        '
        Me.Button1.Dock = System.Windows.Forms.DockStyle.Right
        Me.Button1.Font = New System.Drawing.Font( _
            "Microsoft Sans Serif", _
            9.0!, _
            System.Drawing.FontStyle.Regular, _
            System.Drawing.GraphicsUnit.Point, _
            CType(0, Byte))
        Me.Button1.Location = New System.Drawing.Point(446, 20)
        Me.Button1.Name = "Button1"
        Me.Button1.Size = New System.Drawing.Size(75, 24)
        Me.Button1.TabIndex = 2
        Me.Button1.Text = "&Run"
        '
        'Button2
        '
        Me.Button2.Dock = System.Windows.Forms.DockStyle.Right
        Me.Button2.Font = New System.Drawing.Font( _
            "Microsoft Sans Serif", _
            9.0!, _
            System.Drawing.FontStyle.Regular, _
            System.Drawing.GraphicsUnit.Point, _
            CType(0, Byte))
        Me.Button2.Location = New System.Drawing.Point(521, 20)
        Me.Button2.Name = "Button2"
        Me.Button2.Size = New System.Drawing.Size(75, 24)
        Me.Button2.TabIndex = 3
        Me.Button2.Text = "E&xit"
        '
        'Panel1
        '
        Me.Panel1.Controls.Add(Me.tbxOutput)
        Me.Panel1.Dock = System.Windows.Forms.DockStyle.Fill
        Me.Panel1.DockPadding.All = 20
        Me.Panel1.Location = New System.Drawing.Point(0, 0)
        Me.Panel1.Name = "Panel1"
        Me.Panel1.Size = New System.Drawing.Size(616, 320)
        Me.Panel1.TabIndex = 2
        '
        'tbxOutput
        '
        Me.tbxOutput.AccessibleDescription = _
            "Displays output from application."
        Me.tbxOutput.AccessibleName = "Output textbox."
        Me.tbxOutput.Dock = System.Windows.Forms.DockStyle.Fill
        Me.tbxOutput.Location = New System.Drawing.Point(20, 20)
        Me.tbxOutput.Name = "tbxOutput"
        Me.tbxOutput.Size = New System.Drawing.Size(576, 280)
        Me.tbxOutput.TabIndex = 1
        Me.tbxOutput.Text = "Click the Run button to run the application."
        '
        'Form1
        '
        Me.AutoScaleBaseSize = New System.Drawing.Size(6, 15)
        Me.ClientSize = New System.Drawing.Size(616, 384)
        Me.Controls.Add(Me.Panel1)
        Me.Controls.Add(Me.Panel2)
        Me.Name = "Form1"
        Me.Text = "CryptographicException"
        Me.Panel2.ResumeLayout(False)
        Me.Panel1.ResumeLayout(False)
        Me.ResumeLayout(False)

    End Sub

#End Region
End Class