AllowPartiallyTrustedCallersAttribute, classe (System.Security)

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Microsoft Visual Studio 2008/.NET Framework 3.5

D'autres versions sont également disponibles pour :

Microsoft Visual Studio 2005/.NET Framework 2.0

Bibliothèque de classes .NET Framework

AllowPartiallyTrustedCallersAttribute, classe

Mise à jour : novembre 2007

Permet aux assemblys avec nom fort d'être appelés par du code d'un niveau de confiance partiel. Sans cette déclaration, seuls des appelants présentant un niveau de confiance totale sont en mesure d'utiliser de tels assemblys. Cette classe ne peut pas être héritée.

Espace de noms : System.Security
Assembly : mscorlib (dans mscorlib.dll)

Syntaxe

Visual Basic (Déclaration)

<ComVisibleAttribute(True)> _
<AttributeUsageAttribute(AttributeTargets.Assembly, AllowMultiple := False,  _
    Inherited := False)> _
Public NotInheritable Class AllowPartiallyTrustedCallersAttribute _
    Inherits Attribute

Visual Basic (Utilisation)

Dim instance As AllowPartiallyTrustedCallersAttribute

[ComVisibleAttribute(true)]
[AttributeUsageAttribute(AttributeTargets.Assembly, AllowMultiple = false, 
    Inherited = false)]
public sealed class AllowPartiallyTrustedCallersAttribute : Attribute

VisualC++

[ComVisibleAttribute(true)]
[AttributeUsageAttribute(AttributeTargets::Assembly, AllowMultiple = false, 
    Inherited = false)]
public ref class AllowPartiallyTrustedCallersAttribute sealed : public Attribute

/** @attribute ComVisibleAttribute(true) */
/** @attribute AttributeUsageAttribute(AttributeTargets.Assembly, AllowMultiple = false, Inherited = false) */
public final class AllowPartiallyTrustedCallersAttribute extends Attribute

JScript

public final class AllowPartiallyTrustedCallersAttribute extends Attribute

Notes

AllowPartiallyTrustedCallersAttribute n'est efficace que lorsqu'il est appliqué au niveau de l'assembly par un assembly avec nom fort. Pour plus d'informations sur l'application d'attributs au niveau de l'assembly, consultez Application des attributs.

Par défaut, un assembly avec nom fort qui n'applique pas explicitement cet attribut au niveau de l'assembly pour autoriser son utilisation par du code d'un niveau de confiance partiel ne peut être appelé que par d'autres assemblys auxquels la stratégie de sécurité a octroyé un niveau de confiance totale. Cette restriction est appliquée en plaçant un LinkDemand pour FullTrust sur toutes les méthodes publiques ou protégées sur chaque classe accessible publiquement de l'assembly. Les assemblys destinés à être appelés par du code d'un niveau de confiance partiel peuvent déclarer cette intention en utilisant l'attribut AllowPartiallyTrustedCallersAttribute. Cet attribut est déclaré au niveau de l'assembly. Par exemple, la déclaration est [assembly:AllowPartiallyTrustedCallers] en langage C# et <assembly:AllowPartiallyTrustedCallers> en langage Visual Basic.

Attention :
La présence de cet attribut au niveau de l'assembly empêche le comportement par défaut d'appliquer des vérifications de sécurité FullTrust LinkDemand ce qui autorise l'appel de l'assembly par tout autre assembly (d'un niveau de confiance total ou partiel).

En présence de cet attribut, toutes les autres vérifications de sécurité fonctionnent comme prévu, y compris tous les attributs de sécurité déclarative de niveau classe ou méthode présents. Cet attribut bloque uniquement la demande de l'appelant de confiance totale implicite.

Ce n'est pas un attribut de sécurité déclarative mais un attribut normal (il dérive de Attribute et non de SecurityAttribute).

Pour plus d'informations, consultez Utilisation de bibliothèques à partir de code d'un niveau de confiance partiel.

Exemples

L'exemple suivant montre l'utilisation de la classe AllowPartiallyTrustedCallersAttribute.

Visual Basic

' The following HTML code can be used to call the user control in this sample.
'
'<HTML>
'    <BODY>
'        <OBJECT id="usercontrol" classid="usercontrol.dll#UserControl.UserControl1" width="800"
'        height="300" style="font-size:12;">
'        </OBJECT>
'        <p>
'    </BODY>
'</HTML>
' To run this test control you must create a strong name key, snkey.snk, and 
' a code group that gives full trust to assemblies signed with snkey.snk.
' The user control displays an OpenFileDialog box, then displays a text box containing the name of 
' the file selected and a list box that displays the contents of the file.  The selected file must 
' contain text in order for the control to display the data properly.
' Caution  This sample demonstrates the use of the Assert method.  Calling Assert removes the 
' requirement that all code in the call chain must be granted permission to access the specified 
' resource, it can open up security vulnerabilities if used incorrectly or inappropriately. Therefore, 
' it should be used with great caution.  Assert should always be followed with a RevertAssert 
' command to restore the security settings.

Imports System
Imports System.Collections
Imports System.ComponentModel
Imports System.Drawing
Imports System.Data
Imports System.Windows.Forms
Imports System.IO
Imports System.Security
Imports System.Security.Permissions
Imports System.Reflection
Imports System.Runtime.CompilerServices
Imports Microsoft.VisualBasic


' This strong name key is used to create a code group that gives permissions to this assembly.

<Assembly: AssemblyKeyFile("snKey.snk")> 

<Assembly: AssemblyVersion("1.0.0.0")> 
' The AllowPartiallyTrustedCallersAttribute requires the assembly to be signed with a strong name key.
' This attribute is necessary since the control is called by either an intranet or Internet
' Web page that should be running under restricted permissions.

<Assembly: AllowPartiallyTrustedCallers()> 

' The userControl1 displays an OpenFileDialog box, then displays a text box containing the name of 
' the file selected and a list box that displays the contents of the file.  The selected file must 
' contain text in order for the control to display the data properly.

'Demand the zone requirement for the calling application.
<ZoneIdentityPermissionAttribute(SecurityAction.Demand, Zone:=SecurityZone.Intranet)> _
Public Class UserControl1
    Inherits System.Windows.Forms.UserControl
    Private WithEvents textBox1 As System.Windows.Forms.TextBox
    Private listBox1 As System.Windows.Forms.ListBox
    ' Required designer variable.
    Private components As System.ComponentModel.Container = Nothing


    Public Sub New()
        ' This call is required by the Windows.Forms Form Designer.
        InitializeComponent()

        ' The OpenFileDialog box should not require any special permissions.
        Dim fileDialog As New OpenFileDialog
        If fileDialog.ShowDialog() = DialogResult.OK Then
            ' Reading the name of the selected file from the OpenFileDialog box
            ' and reading the file requires FileIOPermission.  The user control should 
            ' have this permission granted through its code group; the Web page that calls the 
            ' control should not have this permission.  The Assert command prevents a stack walk 
            ' that would fail because the caller does not have the required FileIOPermission.  
            ' The use of Assert can open up security vulnerabilities if used incorrectly or 
            ' inappropriately. Therefore, it should be used with great caution.
            ' The Assert command should be followed by a RevertAssert as soon as the file operation 
            ' is completed.
            Dim fileIOPermission As New FileIOPermission(PermissionState.Unrestricted)
            fileIOPermission.Assert()
            textBox1.Text = fileDialog.FileName
            ' Display the contents of the file in the text box.
            Dim fsIn As New FileStream(textBox1.Text, FileMode.Open, FileAccess.Read, FileShare.Read)
            Dim sr As New StreamReader(fsIn)

            ' Process every line in the file
            Dim Line As String
            Line = sr.ReadLine()
            While Not (Line Is Nothing)
                listBox1.Items.Add(Line)
                Line = sr.ReadLine()
            End While
            ' It is very important to call RevertAssert to restore the stack walk for
            ' file operations.
            fileIOPermission.RevertAssert()
        End If
    End Sub 'New


    ' Clean up any resources being used.
    Protected Overloads 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 'Dispose


    ' Required method for Designer support - do not modify 
    ' the contents of this method with the code editor.
    Private Sub InitializeComponent()
        Me.textBox1 = New System.Windows.Forms.TextBox
        Me.listBox1 = New System.Windows.Forms.ListBox
        Me.SuspendLayout()
        ' 
        ' textBox1
        ' 
        Me.textBox1.Location = New System.Drawing.Point(208, 112)
        Me.textBox1.Name = "textBox1"
        Me.textBox1.Size = New System.Drawing.Size(320, 20)
        Me.textBox1.TabIndex = 0
        Me.textBox1.Text = "textBox1"
        ' 
        ' listBox1
        ' 
        Me.listBox1.Location = New System.Drawing.Point(200, 184)
        Me.listBox1.Name = "listBox1"
        Me.listBox1.Size = New System.Drawing.Size(336, 108)
        Me.listBox1.TabIndex = 1
        ' 
        ' UserControl1
        ' 
        Me.Controls.Add(listBox1)
        Me.Controls.Add(textBox1)
        Me.Name = "UserControl1"
        Me.Size = New System.Drawing.Size(592, 400)
        Me.ResumeLayout(False)
    End Sub 'InitializeComponent

    Private Sub UserControl1_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles MyBase.Load
    End Sub 'UserControl1_Load

    Private Sub textBox1_TextChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles textBox1.TextChanged
    End Sub 'textBox1_TextChanged
End Class 'UserControl1

// The following HTML code can be used to call the user control in this sample.
//
//<HTML>
//    <BODY>
//        <OBJECT id="usercontrol" classid="usercontrol.dll#UserControl.UserControl1" width="800"
//        height="300" style="font-size:12;">
//        </OBJECT>
//        <p>
//    </BODY>
//</HTML>

// To run this test control you must create a strong name key, snkey.snk, and 
// a code group that gives full trust to assemblies signed with snkey.snk.

// The user control displays an OpenFileDialog box, then displays a text box containing the name of 
// the file selected and a list box that displays the contents of the file.  The selected file must 
// contain text in order for the control to display the data properly.

// Caution  This sample demonstrates the use of the Assert method.  Calling Assert removes the 
// requirement that all code in the call chain must be granted permission to access the specified 
// resource, it can open up security vulnerabilities if used incorrectly or inappropriately. Therefore, 
// it should be used with great caution.  Assert should always be followed with a RevertAssert 
// command to restore the security settings.


using System;
using System.Collections;
using System.ComponentModel;
using System.Drawing;
using System.Data;
using System.Windows.Forms;
using System.IO;
using System.Security;
using System.Security.Permissions;
using System.Reflection;
using System.Runtime.CompilerServices;

// This strong name key is used to create a code group that gives permissions to this assembly.
[assembly: AssemblyKeyFile("snKey.snk")]
[assembly: AssemblyVersion("1.0.0.0")]

// The AllowPartiallyTrustedCallersAttribute requires the assembly to be signed with a strong name key.
// This attribute is necessary since the control is called by either an intranet or Internet
// Web page that should be running under restricted permissions.
[assembly:AllowPartiallyTrustedCallers]
namespace UserControl
{
    // The userControl1 displays an OpenFileDialog box, then displays a text box containing the name of 
    // the file selected and a list box that displays the contents of the file.  The selected file must 
    // contain text in order for the control to display the data properly.
    public class UserControl1 : System.Windows.Forms.UserControl
    {
        private System.Windows.Forms.TextBox textBox1;
        private System.Windows.Forms.ListBox listBox1;
        // Required designer variable.
        private System.ComponentModel.Container components = null;

              // Demand the zone requirement for the calling application.
              [ZoneIdentityPermission(SecurityAction.Demand, Zone = SecurityZone.Intranet)]
        public UserControl1()
        {
            // This call is required by the Windows.Forms Form Designer.
            InitializeComponent();

            // The OpenFileDialog box should not require any special permissions.
            OpenFileDialog fileDialog = new OpenFileDialog();
            if(fileDialog.ShowDialog() == DialogResult.OK)
            {
                // Reading the name of the selected file from the OpenFileDialog box
                // and reading the file requires FileIOPermission.  The user control should 
                // have this permission granted through its code group; the Web page that calls the 
                // control should not have this permission.  The Assert command prevents a stack walk 
                // that would fail because the caller does not have the required FileIOPermission.  
                // The use of Assert can open up security vulnerabilities if used incorrectly or 
                // inappropriately. Therefore, it should be used with great caution.
                // The Assert command should be followed by a RevertAssert as soon as the file operation 
                // is completed.
                new FileIOPermission(PermissionState.Unrestricted).Assert();
                textBox1.Text = fileDialog.FileName;
                // Display the contents of the file in the text box.
                FileStream fsIn = new FileStream(textBox1.Text, FileMode.Open, FileAccess.Read, 
                    FileShare.Read);
                StreamReader sr = new StreamReader(fsIn);
            
                // Process every line in the file
                for (String Line = sr.ReadLine(); Line != null; Line = sr.ReadLine()) 
                {
                    listBox1.Items.Add(Line);
                }
                // It is very important to call RevertAssert to restore the stack walk for
                // file operations.
                FileIOPermission.RevertAssert();
            }

        }

        // Clean up any resources being used.
        protected override void Dispose( bool disposing )
        {
            if( disposing )
            {
                if( components != null )
                    components.Dispose();
            }
            base.Dispose( disposing );
        }

        #region Component Designer generated code
        /// <summary>
        /// Required method for Designer support - do not modify 
        /// the contents of this method with the code editor.
        /// </summary>
        private void InitializeComponent()
        {
            this.textBox1 = new System.Windows.Forms.TextBox();
            this.listBox1 = new System.Windows.Forms.ListBox();
            this.SuspendLayout();
            // 
            // textBox1
            // 
            this.textBox1.Location = new System.Drawing.Point(208, 112);
            this.textBox1.Name = "textBox1";
            this.textBox1.Size = new System.Drawing.Size(320, 20);
            this.textBox1.TabIndex = 0;
            this.textBox1.Text = "textBox1";
            this.textBox1.TextChanged += new System.EventHandler(this.textBox1_TextChanged);
            // 
            // listBox1
            // 
            this.listBox1.Location = new System.Drawing.Point(200, 184);
            this.listBox1.Name = "listBox1";
            this.listBox1.Size = new System.Drawing.Size(336, 108);
            this.listBox1.TabIndex = 1;
            // 
            // UserControl1
            // 
            this.Controls.Add(this.listBox1);
            this.Controls.Add(this.textBox1);
            this.Name = "UserControl1";
            this.Size = new System.Drawing.Size(592, 400);
            this.Load += new System.EventHandler(this.UserControl1_Load);
            this.ResumeLayout(false);

        }
        #endregion

        private void UserControl1_Load(object sender, System.EventArgs e)
        {
        
        }

        private void textBox1_TextChanged(object sender, System.EventArgs e)
        {
        
        }


    }
}

Hiérarchie d'héritage

System..::.Object
System..::.Attribute
System.Security..::.AllowPartiallyTrustedCallersAttribute

Sécurité des threads

Tous les membres static (Shared en Visual Basic) publics de ce type sont thread-safe. Il n'est pas garanti que les membres d'instance soient thread-safe.

Plateformes

Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professionnel Édition x64, Windows XP Starter Edition, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98

Le .NET Framework et le .NET Compact Framework ne prennent pas en charge toutes les versions de chaque plateforme. Pour obtenir la liste des versions prises en charge, consultez Configuration requise du .NET Framework.

Informations de version

.NET Framework

Pris en charge dans : 3.5, 3.0, 2.0, 1.1, 1.0

Voir aussi

Référence

Membres AllowPartiallyTrustedCallersAttribute

System.Security, espace de noms

Mots clés

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