AllowPartiallyTrustedCallersAttribute 类

定义

命名空间:

System.Security

程序集:

netstandard.dll, System.Runtime.dll

Source:

AllowPartiallyTrustedCallersAttribute.cs

允许部分受信任的代码调用程序集。 如果没有此声明，只有完全受信任的调用方才能使用该程序集。 无法继承此类。

C#

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

继承

Object

Attribute

AllowPartiallyTrustedCallersAttribute

属性

AttributeUsageAttribute

示例

以下示例演示如何使用 AllowPartiallyTrustedCallersAttribute 类。

C#

// 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)
        {
        }
    }
}

注解

重要

不再支持部分受信任的代码。 此属性在 .NET Core 中不起作用。

备注

.NET Framework 4 引入了影响 AllowPartiallyTrustedCallersAttribute 属性行为的新安全规则（请参阅 Security-Transparent 代码级别 2）。 在 .NET Framework 4 中，所有代码默认为安全透明，即部分信任。 但是，可以批注各个类型和成员以为其分配其他透明度属性。 有关此更改和其他安全更改，请参阅 安全更改。

.NET Framework 版本 2.0 （） 程序集必须具有强名称才能有效地使用 AllowPartiallyTrustedCallersAttribute （APTCA） 属性。 .NET Framework 4 （） 程序集不必为 APTCA 属性提供强名称才能有效，并且它们可以包含透明、安全关键和安全关键代码。 有关在程序集级别应用属性的详细信息，请参阅 应用属性。

默认情况下，如果强名称程序集未在程序集级别显式应用此属性，则只能由被授予完全信任的其他程序集调用此属性。 通过将 FullTrustLinkDemand 放置在程序集中每个可公开访问的类或受保护的方法上，来强制实施此限制。 旨在由部分受信任的代码调用的程序集可以通过使用 AllowPartiallyTrustedCallersAttribute来声明其意图。 C# 中的声明示例是 [assembly:AllowPartiallyTrustedCallers];Visual Basic 中的一个示例是 <assembly:AllowPartiallyTrustedCallers>。

注意

此程序集级属性的存在可防止默认行为放置 FullTrustLinkDemand 安全检查，并使程序集可从任何其他（部分或完全信任）程序集调用。

当 APTCA 属性存在时，所有其他安全检查都按预期运行，包括存在的任何类级或方法级声明性安全属性。 此属性仅阻止隐式完全受信任的调用方需求。

这不是声明性安全属性，而是常规属性（它派生自 System.Attribute，而不是从 System.Security.Permissions.SecurityAttribute派生）。

有关详细信息，请参阅 使用部分受信任的代码的库。

构造函数

AllowPartiallyTrustedCallersAttribute()

初始化 AllowPartiallyTrustedCallersAttribute 类的新实例。

属性

PartialTrustVisibilityLevel	获取或设置使用 AllowPartiallyTrustedCallersAttribute （APTCA） 属性标记的代码的默认部分信任可见性。
TypeId	在派生类中实现时，获取此 Attribute的唯一标识符。 (继承自 Attribute)

方法

Equals(Object)	返回一个值，该值指示此实例是否等于指定对象。 (继承自 Attribute)
GetHashCode()	返回此实例的哈希代码。 (继承自 Attribute)
GetType()	获取当前实例的 Type。 (继承自 Object)
IsDefaultAttribute()	在派生类中重写时，指示此实例的值是否为派生类的默认值。 (继承自 Attribute)
Match(Object)	在派生类中重写时，返回一个值，该值指示此实例是否等于指定对象。 (继承自 Attribute)
MemberwiseClone()	创建当前 Object的浅表副本。 (继承自 Object)
ToString()	返回一个表示当前对象的字符串。 (继承自 Object)

适用于