FileDialogPermissionAccess Enumeration
Specifies the type of access to files allowed through the File dialog boxes.
This enumeration has a FlagsAttribute attribute that allows a bitwise combination of its member values.
Namespace: System.Security.PermissionsAssembly: mscorlib (in mscorlib.dll)
The following code example demonstrates the declarative and imperative forms of the FileDialogPermission class by using the FileDialogPermissionAccess enumeration to specify the type of access that is to be allowed through the File dialog boxes.
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.
Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98
The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.