FileDialogPermission-Konstruktor (FileDialogPermissionAccess)

Initialisiert eine neue Instanz der FileDialogPermission-Klasse mit dem angegebenen Zugriff.

Namespace: System.Security.Permissions
Assembly: mscorlib (in mscorlib.dll)

Syntax

'Declaration
Public Sub New ( _
    access As FileDialogPermissionAccess _
)
'Usage
Dim access As FileDialogPermissionAccess

Dim instance As New FileDialogPermission(access)

public FileDialogPermission (
    FileDialogPermissionAccess access
)

public:
FileDialogPermission (
    FileDialogPermissionAccess access
)

public FileDialogPermission (
    FileDialogPermissionAccess access
)

public function FileDialogPermission (
    access : FileDialogPermissionAccess
)

Parameter

• access
  Eine bitweise Kombination der FileDialogPermissionAccess-Werte.

Ausnahmen

Ausnahmetyp	Bedingung
ArgumentException	Der access-Parameter ist keine gültige Kombination von FileDialogPermissionAccess-Werten.

Beispiel

Im folgenden Codebeispiel wird die deklarative und imperative Form der FileDialogPermission-Klasse veranschaulicht. Der erste Versuch, das Dialogfeld anzuzeigen, ist erfolgreich. Jeder weitere Versuch schlägt fehl, weil die Main-Methode ein Deny ausgibt. In der Klasse wird deklarative Sicherheit verwendet, um die zum Ausführen des Codes in der Klasse erforderlichen Mindestberechtigungen anzufordern.

Imports System
Imports System.Security
Imports System.Security.Permissions
Imports System.Windows.Forms
Imports System.IO

' Declare FileDialogPermissionAttribute declaratively to request minimum
' permissions for the code in this class to run.
<Assembly: FileDialogPermissionAttribute( _
    SecurityAction.RequestMinimum, Open:=True)> 

Public Class Form1
    Inherits System.Windows.Forms.Form

    Private fileStream As Stream

    ' 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 = ""

        tbxOutput.AppendText("Opened file " + OpenFile() + vbCrLf)

        ' Deny permission to use of the Open dialog box.
        Dim dialogPermission As _
            New FileDialogPermission(FileDialogPermissionAccess.Open)

        dialogPermission.Deny()

        OpenFile()
        CloseStream()

        ' Align interface and conclude application.
        tbxOutput.AppendText(vbCrLf + "This sample completed " + _
            "successfully; press Exit to continue.")

        ' Reset the cursor.
        tbxOutput.Cursor = Cursors.Default
    End Sub
    ' Display open dialog box, store the file stream of the specified file
    ' in the fileStream member variable.
    Private Function OpenFile() As String
        Dim fileName As String

        Dim openDialogBox As New OpenFileDialog
        openDialogBox.InitialDirectory = "c:\"
        openDialogBox.Filter = "txt files (*.txt)|*.txt"
        openDialogBox.RestoreDirectory = True

        Try
            ' If user selects OK, store file name and stream.
            If (openDialogBox.ShowDialog() = DialogResult.OK) Then
                fileName = openDialogBox.FileName
                fileStream = openDialogBox.OpenFile()
                fileStream.Close()
            End If

        Catch ex As Exception
            tbxOutput.AppendText(ex.Message + vbCrLf)
        End Try

        openDialogBox.Dispose()

        ' Return specified file name.
        Return fileName

    End Function
    ' Close the file stream.
    Private Sub CloseStream()
        If Not fileStream Is Nothing Then
            fileStream.Close()
        End If
    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 = "FileDialogPermission"
        Me.Panel2.ResumeLayout(False)
        Me.Panel1.ResumeLayout(False)
        Me.ResumeLayout(False)

    End Sub

#End Region
End Class
'
' This sample produces the following output:
'
' Opened file C:\testfile.txt
' Request for the permission of type 
' System.Security.Permissions.FileDialogPermission, mscorlib, 
' Version=1.0.5000.0, Culture=neutral, PublicKeyToken=b77a5c561934e089 failed.
'
' This sample completed successfully; press Exit to continue.

using System;
using System.Security;
using System.Security.Permissions;
using System.Windows.Forms;
using System.IO;

// Add the declarative FileDialogPermissionAttribute to request minimum
// permissions for the code in this class to run.
[assembly:FileDialogPermissionAttribute(
    SecurityAction.RequestMinimum, 
    Open=true)]
public class DialogPermissions
{
    private Stream fileStream;

    public static void Main()
    {
        DialogPermissions dialogAccess = new DialogPermissions();
        Console.WriteLine("Opened file " + dialogAccess.OpenFile());

        // Deny permission to use of the Open dialog box.
        FileDialogPermission dialogPermission = 
            new FileDialogPermission(FileDialogPermissionAccess.Open);

        dialogPermission.Deny();

        dialogAccess.OpenFile();
        dialogAccess.CloseStream();

    }

    // Display open dialog box, store the file stream of the specified file
    // in the fileStream member variable.
    private string OpenFile()
    {
        string fileName = null;

        OpenFileDialog openDialogBox = new OpenFileDialog();
        openDialogBox.InitialDirectory = "c:\\";
        openDialogBox.Filter = "txt files (*.txt)|*.txt";
        openDialogBox.RestoreDirectory = true;
        try
        {
            // If user selects OK, store file name and stream.
            if(openDialogBox.ShowDialog() == DialogResult.OK)
            {
                fileName = openDialogBox.FileName;
                fileStream = openDialogBox.OpenFile();
                fileStream.Close();
            }
        }
        catch (Exception ex)
        {
            Console.WriteLine(ex.Message);
        }

        openDialogBox.Dispose();

        // Return specified file name.
        return fileName;
    }

    // Close the file stream.
    private void CloseStream()
    {
        if (fileStream != null)
        {
            fileStream.Close();
        }
    }
}
//
// This sample produces the following output:
//
// Opened file C:\testfile.txt
// Request for the permission of type 
// System.Security.Permissions.FileDialogPermission, mscorlib, 
// Version=1.0.5000.0, Culture=neutral, PublicKeyToken=b77a5c561934e089 
// failed.
//
// This sample completed successfully; press Exit to continue.

import System.*;
import System.Security.*;
import System.Security.Permissions.*;
import System.Windows.Forms.*;
import System.IO.*;

// Add the declarative FileDialogPermissionAttribute to request minimum
// permissions for the code in this class to run.
/** @assembly FileDialogPermissionAttribute(SecurityAction.RequestMinimum,
    Open = true)
 */
public class DialogPermissions
{    
    private Stream fileStream;

    public static void main(String[] args)
    {
        DialogPermissions dialogAccess = new DialogPermissions();
        Console.WriteLine("Opened file " + dialogAccess.OpenFile());

        // Deny permission to use of the Open dialog box.
        FileDialogPermission dialogPermission = 
            new FileDialogPermission(FileDialogPermissionAccess.Open);
        dialogPermission.Deny();

        dialogAccess.OpenFile();
        dialogAccess.CloseStream();
    } //main

    // Display open dialog box, store the file stream of the specified file
    // in the fileStream member variable.
    private String OpenFile()
    {
        String fileName = null;

        OpenFileDialog openDialogBox = new OpenFileDialog();
        openDialogBox.set_InitialDirectory("c:\\");
        openDialogBox.set_Filter("txt files (*.txt)|*.txt");
        openDialogBox.set_RestoreDirectory(true);
        try {
            // If user selects OK, store file name and stream.
            if (openDialogBox.ShowDialog().Equals(DialogResult.OK)) {
                fileName = openDialogBox.get_FileName();
                fileStream = openDialogBox.OpenFile();
                fileStream.Close();
            }
        }
        catch (System.Exception ex) {
            Console.WriteLine(ex.get_Message());
        }
        openDialogBox.Dispose();
        // Return specified file name.
        return fileName;
    } //OpenFile

    // Close the file stream.
    private void CloseStream()
    {
        if (fileStream != null) {
            fileStream.Close();
        }
    } //CloseStream
} //DialogPermissions
//
// This sample produces the following output:
//
// Opened file C:\testfile.txt
// Request for the permission of type 
// System.Security.Permissions.FileDialogPermission, mscorlib, 
// Version=1.0.5000.0, Culture=neutral, PublicKeyToken=b77a5c561934e089 
// failed.
//
// This sample completed successfully; press Exit to continue.

Plattformen

Windows 98, Windows 2000 SP4, Windows Millennium Edition, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

.NET Framework unterstützt nicht alle Versionen sämtlicher Plattformen. Eine Liste der unterstützten Versionen finden Sie unter Systemanforderungen.

Versionsinformationen

.NET Framework

Unterstützt in: 2.0, 1.1, 1.0

Siehe auch

Referenz

FileDialogPermission-Klasse
FileDialogPermission-Member
System.Security.Permissions-Namespace