AllowPartiallyTrustedCallersAttribute Classe

Definizione

Spazio dei nomi:

System.Security

Assembly:

System.Runtime.dll

Source:

AllowPartiallyTrustedCallersAttribute.cs

Consente a un assembly di essere chiamato da codice parzialmente attendibile. In assenza di questa dichiarazione, solo i chiamanti completamente attendibili potranno usare l'assembly. La classe non può essere ereditata.

public ref class AllowPartiallyTrustedCallersAttribute sealed : Attribute

[System.AttributeUsage(System.AttributeTargets.Assembly, AllowMultiple=false, Inherited=false)]
public sealed class AllowPartiallyTrustedCallersAttribute : Attribute

[<System.AttributeUsage(System.AttributeTargets.Assembly, AllowMultiple=false, Inherited=false)>]
type AllowPartiallyTrustedCallersAttribute = class
    inherit Attribute

Public NotInheritable Class AllowPartiallyTrustedCallersAttribute
Inherits Attribute

Ereditarietà

Object

Attribute

AllowPartiallyTrustedCallersAttribute

Attributi

AttributeUsageAttribute

Esempio

Nell'esempio seguente viene illustrato come utilizzare la classe AllowPartiallyTrustedCallersAttribute.

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

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

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

[assembly:AssemblyKeyFile("snKey.snk")];
[assembly:AssemblyVersion("1.0.0.0")];
[assembly:AllowPartiallyTrustedCallers];
public ref class UserControl1: public System::Windows::Forms::UserControl
{
private:
   System::Windows::Forms::TextBox^ textBox1;
   System::Windows::Forms::ListBox^ listBox1;

   // Required designer variable.
   System::ComponentModel::Container^ components;

public:
// Demand the zone requirement for the calling application.
[ZoneIdentityPermission(SecurityAction::Demand, Zone = SecurityZone::Intranet)]
   UserControl1()
   {
      
      // This call is required by the Windows.Forms Form Designer.
      InitializeComponent();
      
      // The OpenFileDialog box should not require any special permissions.
      OpenFileDialog^ fileDialog = gcnew 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.
         (gcnew FileIOPermission( PermissionState::Unrestricted ))->Assert();
         textBox1->Text = fileDialog->FileName;

         // Display the contents of the file in the text box.
         FileStream^ fsIn = gcnew FileStream( textBox1->Text,FileMode::Open,FileAccess::Read,FileShare::Read );
         StreamReader^ sr = gcnew StreamReader( fsIn );
         
         // Process every line in the file
         for ( String ^ Line = sr->ReadLine(); Line != nullptr; Line = sr->ReadLine() )
         {
            listBox1->Items->Add( Line );

         }

         // file operations.
         FileIOPermission::RevertAssert();
      }
   }

private:

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

   void UserControl1_Load( Object^ /*sender*/, System::EventArgs^ /*e*/ ){}

   void textBox1_TextChanged( Object^ /*sender*/, System::EventArgs^ /*e*/ ){}

};

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

// 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)
        {
        }
    }
}

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

' 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


    ' 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


    ' 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

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

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

Commenti

Importante

Il codice parzialmente attendibile non è più supportato. Questo attributo non ha alcun effetto in .NET Core.

Nota

.NET Framework 4 introduce nuove regole di sicurezza che influiscono sul comportamento dell'attributo AllowPartiallyTrustedCallersAttribute (vedere Security-Transparent Code, Livello 2). In .NET Framework 4, per impostazione predefinita, tutto il codice è trasparente per la sicurezza, ovvero parzialmente attendibile. Tuttavia, è possibile annotare singoli tipi e membri per assegnarli ad altri attributi di trasparenza. Per questa e altre modifiche alla sicurezza, vedere Modifiche alla sicurezza.

Gli assembly .NET Framework versione 2.0 () devono essere denominati con nome sicuro per usare in modo efficace l'attributo AllowPartiallyTrustedCallersAttribute (APTCA). Gli assembly .NET Framework 4 () non devono essere denominati con nome sicuro per l'attributo APTCA in modo efficace e possono contenere codice trasparente, critico per la sicurezza e critico per la sicurezza. Per altre informazioni sull'applicazione di attributi a livello di assembly, vedere Applicazione di attributi.

Per impostazione predefinita, se un assembly con nome sicuro non applica in modo esplicito questo attributo a livello di assembly, può essere chiamato solo da altri assembly a cui viene concessa l'attendibilità totale. Questa restrizione viene applicata inserendo un LinkDemand per in FullTrust ogni metodo pubblico o protetto in ogni classe accessibile pubblicamente nell'assembly. Gli assembly che devono essere chiamati da codice parzialmente attendibile possono dichiarare la finalità tramite l'uso di AllowPartiallyTrustedCallersAttribute. Un esempio della dichiarazione in C# è [assembly:AllowPartiallyTrustedCallers]. Un esempio in Visual Basic è <assembly:AllowPartiallyTrustedCallers>.

Attenzione

La presenza di questo attributo a livello di assembly impedisce il comportamento predefinito di inserimento FullTrustLinkDemand dei controlli di sicurezza e rende l'assembly chiamabile da qualsiasi altro assembly (parzialmente o completamente attendibile).

Quando l'attributo APTCA è presente, tutti gli altri controlli di sicurezza funzionano come previsto, inclusi tutti gli attributi di sicurezza dichiarativi a livello di classe o a livello di metodo presenti. Questo attributo blocca solo la richiesta implicita e completamente attendibile del chiamante.

Non si tratta di un attributo di sicurezza dichiarativo, ma di un attributo regolare (deriva da System.Attribute, non da System.Security.Permissions.SecurityAttribute).

Per altre informazioni, vedere Uso di librerie da codice parzialmente attendibile.

Costruttori

AllowPartiallyTrustedCallersAttribute()

Inizializza una nuova istanza della classe AllowPartiallyTrustedCallersAttribute.

Proprietà

PartialTrustVisibilityLevel	Ottiene o imposta la visibilità predefinita in un contesto parzialmente attendibile del codice contrassegnato con l'attributo AllowPartiallyTrustedCallersAttribute (APTCA).
TypeId	Quando è implementata in una classe derivata, ottiene un identificatore univoco della classe Attribute. (Ereditato da Attribute)

Metodi

Equals(Object)	Restituisce un valore che indica se questa istanza è uguale a un oggetto specificato. (Ereditato da Attribute)
GetHashCode()	Restituisce il codice hash per l'istanza. (Ereditato da Attribute)
GetType()	Ottiene l'oggetto Type dell'istanza corrente. (Ereditato da Object)
IsDefaultAttribute()	In caso di override in una classe derivata, indica se il valore di questa istanza è il valore predefinito per la classe derivata. (Ereditato da Attribute)
Match(Object)	Quando è sottoposto a override in una classe derivata, restituisce un valore che indica se questa istanza equivale a un oggetto specificato. (Ereditato da Attribute)
MemberwiseClone()	Crea una copia superficiale dell'oggetto Object corrente. (Ereditato da Object)
ToString()	Restituisce una stringa che rappresenta l'oggetto corrente. (Ereditato da Object)