ISecurityEncodable Интерфейс

Определение

Пространство имен:

System.Security

Сборка:

System.Runtime.dll

Определяет методы, которые преобразуют состояние объекта разрешений в представление элемента XML и обратно.

public interface class ISecurityEncodable

public interface ISecurityEncodable

type ISecurityEncodable = interface

Public Interface ISecurityEncodable

Производный

System.IdentityModel.Services.ClaimsPrincipalPermission

System.Security.CodeAccessPermission

System.Security.IPermission

System.Security.Permissions.PrincipalPermission

System.Security.PermissionSet

System.Security.Policy.AllMembershipCondition

System.Security.Policy.ApplicationDirectoryMembershipCondition

System.Security.Policy.ApplicationTrust

System.Security.Policy.GacMembershipCondition

System.Security.Policy.HashMembershipCondition

System.Security.Policy.IApplicationTrustManager

System.Security.Policy.IMembershipCondition

System.Security.Policy.PolicyStatement

System.Security.Policy.PublisherMembershipCondition

System.Security.Policy.SiteMembershipCondition

System.Security.Policy.StrongNameMembershipCondition

System.Security.Policy.UrlMembershipCondition

System.Security.Policy.ZoneMembershipCondition

Примеры

В этом примере показано, как определить класс разрешений для использования с безопасностью доступа к коду. Реализованы все необходимые интерфейсы разрешений.

using namespace System;
using namespace System::Security;
using namespace System::Security::Permissions;
using namespace System::Reflection;

// Enumerated type for permission states.
[Serializable]
public enum class SoundPermissionState
{
    NoSound = 0,
    PlaySystemSounds = 1,
    PlayAnySound = 2
};

// Derive from CodeAccessPermission to gain implementations of the following
// sealed IStackWalk methods: Assert, Demand, Deny, and PermitOnly.
// Implement the following abstract IPermission methods: 
// Copy, Intersect, and IsSubSetOf.
// Implementing the Union method of the IPermission class is optional.
// Implement the following abstract ISecurityEncodable methods: 
// FromXml and ToXml.
// Making the class 'sealed' is optional.

public ref class SoundPermission sealed : public CodeAccessPermission, 
    public IPermission, public IUnrestrictedPermission, 
    public ISecurityEncodable, public ICloneable
{
private:
    bool specifiedAsUnrestricted;
private:
    SoundPermissionState stateFlags;

    // This constructor creates and initializes 
    // a permission with generic access.
public:
    SoundPermission(PermissionState^ state)
    {
        specifiedAsUnrestricted = (state == PermissionState::Unrestricted);
    }

    // This constructor creates and initializes 
    // a permission with specific access.
public:
    SoundPermission(SoundPermissionState flags)
    {
        if (flags < SoundPermissionState::NoSound ||
            flags > SoundPermissionState::PlayAnySound)
        {
            throw gcnew ArgumentException("The value of \"flags\" is not" +
                " valid for the SoundPermissionState enumerated type");
        }
        stateFlags = flags;
    }

    // For debugging, return the state of this object as XML.
public:
    virtual String^ ToString() override
    {
        return ToXml()->ToString();
    }

    // Private method to cast (if possible) an IPermission to the type.
private:
    SoundPermission^ VerifyTypeMatch(IPermission^ target)
    {
        if (GetType() != target->GetType())
        {
            throw gcnew ArgumentException(String::Format(
                "The variable \"target\" must be of the {0} type",
                GetType()->FullName));
        }
        return (SoundPermission^) target;
    }

    // This is the Private Clone helper method.
private:
    SoundPermission^ Clone(bool specifiedAsUnrestricted, 
        SoundPermissionState flags)
    {
        SoundPermission^ soundPerm = (SoundPermission^) Clone();
        soundPerm->specifiedAsUnrestricted = specifiedAsUnrestricted;
        soundPerm->stateFlags = specifiedAsUnrestricted ? 
            SoundPermissionState::PlayAnySound : flags;
        return soundPerm;
    }

    #pragma region IPermission^ Members
    // Return a new object that contains the intersection 
    // of 'this' and 'target'.
public:
    virtual IPermission^ Intersect(IPermission^ target) override
    {
        // If 'target' is null, return null.
        if (target == nullptr)
        {
            return nullptr;
        }

        // Both objects must be the same type.
        SoundPermission^ soundPerm = VerifyTypeMatch(target);

        // If 'this' and 'target' are unrestricted, 
        // return a new unrestricted permission.
        if (specifiedAsUnrestricted && soundPerm->specifiedAsUnrestricted)
        {
            return Clone(true, SoundPermissionState::PlayAnySound);
        }

        // Calculate the intersected permissions. 
        // If there are none, return null.
        SoundPermissionState minimumPermission = (SoundPermissionState)
            Math::Min((int) stateFlags, (int) soundPerm->stateFlags);
        if ((int)minimumPermission == 0)
        {
            return nullptr;
        }

        // Return a new object with the intersected permission value.
        return Clone(false, minimumPermission);
    }

    // Called by the Demand method: returns true 
    // if 'this' is a subset of 'target'.
public:
    virtual bool IsSubsetOf(IPermission^ target) override
    {
        // If 'target' is null and this permission allows nothing, 
        // return true.
        if (target == nullptr)
        {
            return (int)stateFlags == 0;
        }

        // Both objects must be the same type.
        SoundPermission^ soundPerm = VerifyTypeMatch(target);

        // Return true if the permissions of 'this' 
        // is a subset of 'target'.
        return stateFlags <= soundPerm->stateFlags;
    }

    // Return a new object that matches 'this' object's permissions.
public:
    virtual IPermission^ Copy () override sealed
    {
        return (IPermission^) Clone();
    }

    // Return a new object that contains the union of 'this' and 'target'.
    // Note: You do not have to implement this method. 
    // If you do not, the version
    // in CodeAccessPermission does this:
    //    1. If target is not null, a NotSupportedException is thrown.
    //    2. If target is null, then Copy is called and 
    //       the new object is returned.
public:
    virtual IPermission^ Union(IPermission^ target) override
    {
        // If 'target' is null, then return a copy of 'this'.
        if (target == nullptr)
        {
            return Copy();
        }

        // Both objects must be the same type.
        SoundPermission^ soundPerm = VerifyTypeMatch(target);

        // If 'this' or 'target' are unrestricted, 
        // return a new unrestricted permission.
        if (specifiedAsUnrestricted || soundPerm->specifiedAsUnrestricted)
        {
            return Clone(true, SoundPermissionState::PlayAnySound);
        }

        // Return a new object with the calculated, unioned permission value.
        return Clone(false, (SoundPermissionState)
            Math::Max((int) stateFlags, (int) soundPerm->stateFlags));
    }
    #pragma endregion

    #pragma region ISecurityEncodable^ Members
    // Populate the permission's fields from XML.
public:
    virtual void FromXml(SecurityElement^ element) override
    {
        specifiedAsUnrestricted = false;
        stateFlags = (SoundPermissionState)0;

        // If XML indicates an unrestricted permission, 
        // make this permission unrestricted.
        String^ attributeString = 
            (String^) element->Attributes["Unrestricted"];
        if (attributeString != nullptr)
        {
            specifiedAsUnrestricted = Convert::ToBoolean(attributeString);
            if (specifiedAsUnrestricted)
            {
                stateFlags = SoundPermissionState::PlayAnySound;
            }
        }

        // If XML indicates a restricted permission, parse the flags.
        if (!specifiedAsUnrestricted)
        {
            attributeString = (String^) element->Attributes["Flags"];
            if (attributeString != nullptr)
            {
                stateFlags = (SoundPermissionState) Convert::ToInt32(
                    Enum::Parse(SoundPermissionState::typeid, 
                    attributeString, true));
            }
        }
    }

    // Produce XML from the permission's fields.
public:
    virtual SecurityElement^ ToXml() override
    {
        // These first three lines create an element with the required format.
        SecurityElement^ element = gcnew SecurityElement("IPermission");
        // Replace the double quotation marks () 
        // with single quotation marks ()
        // to remain XML compliant when the culture is not neutral.
        element->AddAttribute("class", 
            GetType()->AssemblyQualifiedName->Replace('\"', '\''));
        element->AddAttribute("version", "1");

        if (!specifiedAsUnrestricted)
        {
            element->AddAttribute("Flags", 
                Enum::Format(SoundPermissionState::typeid, stateFlags, "G"));
        }   
        else
        {
            element->AddAttribute("Unrestricted", "true");
        }
        return element;
    }
    #pragma endregion

    #pragma region IUnrestrictedPermission^ Members
    // Returns true if permission is effectively unrestricted.
public:
    virtual bool IsUnrestricted()
    {
        // This means that the object is unrestricted at runtime.
        return stateFlags == SoundPermissionState::PlayAnySound;
    }
    #pragma endregion

    #pragma region ICloneable^ Members

    // Return a copy of the permission.
public:
    virtual Object^ Clone()
    {
        return MemberwiseClone();
    }

    #pragma endregion
};

using System;
using System.Security;
using System.Security.Permissions;
using System.Reflection;

// Enumerated type for permission states.
[Serializable]
public enum SoundPermissionState
{
    NoSound = 0,
    PlaySystemSounds = 1,
    PlayAnySound = 2
}

// Derive from CodeAccessPermission to gain implementations of the following
// sealed IStackWalk methods: Assert, Demand, Deny, and PermitOnly.
// Implement the following abstract IPermission methods: Copy, Intersect, and IsSubSetOf.
// Implementing the Union method of the IPermission class is optional.
// Implement the following abstract ISecurityEncodable methods: FromXml and ToXml.
// Making the class 'sealed' is optional.

public sealed class SoundPermission : CodeAccessPermission, IPermission,
    IUnrestrictedPermission, ISecurityEncodable, ICloneable
{
    private Boolean m_specifiedAsUnrestricted = false;
    private SoundPermissionState m_flags = SoundPermissionState.NoSound;

    // This constructor creates and initializes a permission with generic access.
    public SoundPermission(PermissionState state)
    {
        m_specifiedAsUnrestricted = (state == PermissionState.Unrestricted);
    }

    // This constructor creates and initializes a permission with specific access.
    public SoundPermission(SoundPermissionState flags)
    {
        if (!Enum.IsDefined(typeof(SoundPermissionState), flags))
            throw new ArgumentException
                ("flags value is not valid for the SoundPermissionState enuemrated type");
        m_specifiedAsUnrestricted = false;
        m_flags = flags;
    }

    // For debugging, return the state of this object as XML.
    public override String ToString() { return ToXml().ToString(); }

    // Private method to cast (if possible) an IPermission to the type.
    private SoundPermission VerifyTypeMatch(IPermission target)
    {
        if (GetType() != target.GetType())
            throw new ArgumentException(String.Format("target must be of the {0} type",
                GetType().FullName));
        return (SoundPermission)target;
    }

    // This is the Private Clone helper method.
    private SoundPermission Clone(Boolean specifiedAsUnrestricted, SoundPermissionState flags)
    {
        SoundPermission soundPerm = (SoundPermission)Clone();
        soundPerm.m_specifiedAsUnrestricted = specifiedAsUnrestricted;
        soundPerm.m_flags = specifiedAsUnrestricted ? SoundPermissionState.PlayAnySound : m_flags;
        return soundPerm;
    }

    #region IPermission Members
    // Return a new object that contains the intersection of 'this' and 'target'.
    public override IPermission Intersect(IPermission target)
    {
        // If 'target' is null, return null.
        if (target == null) return null;

        // Both objects must be the same type.
        SoundPermission soundPerm = VerifyTypeMatch(target);

        // If 'this' and 'target' are unrestricted, return a new unrestricted permission.
        if (m_specifiedAsUnrestricted && soundPerm.m_specifiedAsUnrestricted)
            return Clone(true, SoundPermissionState.PlayAnySound);

        // Calculate the intersected permissions. If there are none, return null.
        SoundPermissionState val = (SoundPermissionState)
            Math.Min((Int32)m_flags, (Int32)soundPerm.m_flags);
        if (val == 0) return null;

        // Return a new object with the intersected permission value.
        return Clone(false, val);
    }

    // Called by the Demand method: returns true if 'this' is a subset of 'target'.
    public override Boolean IsSubsetOf(IPermission target)
    {
        // If 'target' is null and this permission allows nothing, return true.
        if (target == null) return m_flags == 0;

        // Both objects must be the same type.
        SoundPermission soundPerm = VerifyTypeMatch(target);

        // Return true if the permissions of 'this' is a subset of 'target'.
        return m_flags <= soundPerm.m_flags;
    }

    // Return a new object that matches 'this' object's permissions.
    public sealed override IPermission Copy()
    {
        return (IPermission)Clone();
    }

    // Return a new object that contains the union of 'this' and 'target'.
    // Note: You do not have to implement this method. If you do not, the version
    // in CodeAccessPermission does this:
    //    1. If target is not null, a NotSupportedException is thrown.
    //    2. If target is null, then Copy is called and the new object is returned.
    public override IPermission Union(IPermission target)
    {
        // If 'target' is null, then return a copy of 'this'.
        if (target == null) return Copy();

        // Both objects must be the same type.
        SoundPermission soundPerm = VerifyTypeMatch(target);

        // If 'this' or 'target' are unrestricted, return a new unrestricted permission.
        if (m_specifiedAsUnrestricted || soundPerm.m_specifiedAsUnrestricted)
            return Clone(true, SoundPermissionState.PlayAnySound);

        // Return a new object with the calculated, unioned permission value.
        return Clone(false, (SoundPermissionState)
            Math.Max((Int32)m_flags, (Int32)soundPerm.m_flags));
    }
    #endregion

    #region ISecurityEncodable Members
    // Populate the permission's fields from XML.
    public override void FromXml(SecurityElement e)
    {
        m_specifiedAsUnrestricted = false;
        m_flags = 0;

        // If XML indicates an unrestricted permission, make this permission unrestricted.
        String s = (String)e.Attributes["Unrestricted"];
        if (s != null)
        {
            m_specifiedAsUnrestricted = Convert.ToBoolean(s);
            if (m_specifiedAsUnrestricted)
                m_flags = SoundPermissionState.PlayAnySound;
        }

        // If XML indicates a restricted permission, parse the flags.
        if (!m_specifiedAsUnrestricted)
        {
            s = (String)e.Attributes["Flags"];
            if (s != null)
            {
                m_flags = (SoundPermissionState)
                Convert.ToInt32(Enum.Parse(typeof(SoundPermission), s, true));
            }
        }
    }

    // Produce XML from the permission's fields.
    public override SecurityElement ToXml()
    {
        // These first three lines create an element with the required format.
        SecurityElement e = new SecurityElement("IPermission");
        // Replace the double quotation marks ("") with single quotation marks ('')
        // to remain XML compliant when the culture is not neutral.
        e.AddAttribute("class", GetType().AssemblyQualifiedName.Replace('\"', '\''));
        e.AddAttribute("version", "1");

        if (!m_specifiedAsUnrestricted)
            e.AddAttribute("Flags", Enum.Format(typeof(SoundPermissionState), m_flags, "G"));
        else
            e.AddAttribute("Unrestricted", "true");
        return e;
    }
    #endregion

    #region IUnrestrictedPermission Members
    // Returns true if permission is effectively unrestricted.
    public Boolean IsUnrestricted()
    {
        // This means that the object is unrestricted at runtime.
        return m_flags == SoundPermissionState.PlayAnySound;
    }
    #endregion

    #region ICloneable Members

    // Return a copy of the permission.
    public Object Clone() { return MemberwiseClone(); }

    #endregion
}

Imports System.Security
Imports System.Security.Permissions
Imports System.Reflection


' Enumerated type for permission states.
<Serializable()>  _
Public Enum SoundPermissionState
    NoSound = 0
    PlaySystemSounds = 1
    PlayAnySound = 2
End Enum 'SoundPermissionState

' Derive from CodeAccessPermission to gain implementations of the following
' sealed IStackWalk methods: Assert, Demand, Deny, and PermitOnly.
' Implement the following abstract IPermission methods: Copy, Intersect, and IsSubSetOf.
' Implementing the Union method of the IPermission class is optional.
' Implement the following abstract ISecurityEncodable methods: FromXml and ToXml.
' Making the class 'sealed' is optional.

NotInheritable Public Class SoundPermission
    Inherits CodeAccessPermission
    Implements IPermission, IUnrestrictedPermission, ISecurityEncodable, ICloneable
    Private m_specifiedAsUnrestricted As [Boolean] = False
    Private m_flags As SoundPermissionState = SoundPermissionState.NoSound
    ' This constructor creates and initializes a permission with generic access.
    Public Sub New(ByVal state As PermissionState)
        m_specifiedAsUnrestricted = state = PermissionState.Unrestricted

    End Sub
    ' This constructor creates and initializes a permission with specific access.
    Public Sub New(ByVal flags As SoundPermissionState)
        If Not [Enum].IsDefined(GetType(SoundPermissionState), flags) Then
            Throw New ArgumentException("flags value is not valid for the SoundPermissionState enuemrated type")
        End If
        m_specifiedAsUnrestricted = False
        m_flags = flags

    End Sub
    ' For debugging, return the state of this object as XML.
    Public Overrides Function ToString() As String
        Return ToXml().ToString()

    End Function 'ToString
    ' Private method to cast (if possible) an IPermission to the type.
    Private Function VerifyTypeMatch(ByVal target As IPermission) As SoundPermission
        If [GetType]() <> target.GetType() Then
            Throw New ArgumentException(String.Format("target must be of the {0} type", [GetType]().FullName))
        End If
        Return CType(target, SoundPermission)

    End Function 'VerifyTypeMatch
    ' This is the Private Clone helper method.
    Private Function Clone(ByVal specifiedAsUnrestricted As [Boolean], ByVal flags As SoundPermissionState) As SoundPermission
        Dim soundPerm As SoundPermission = CType(Clone(), SoundPermission)
        soundPerm.m_specifiedAsUnrestricted = specifiedAsUnrestricted
        soundPerm.m_flags = IIf(specifiedAsUnrestricted, SoundPermissionState.PlayAnySound, m_flags)
        Return soundPerm

    End Function 'Clone

#Region "IPermission Members"

    ' Return a new object that contains the intersection of 'this' and 'target'.
    Public Overrides Function Intersect(ByVal target As IPermission) As IPermission
        ' If 'target' is null, return null.
        If target Is Nothing Then
            Return Nothing
        End If
        ' Both objects must be the same type.
        Dim soundPerm As SoundPermission = VerifyTypeMatch(target)

        ' If 'this' and 'target' are unrestricted, return a new unrestricted permission.
        If m_specifiedAsUnrestricted AndAlso soundPerm.m_specifiedAsUnrestricted Then
            Return Clone(True, SoundPermissionState.PlayAnySound)
        End If
        ' Calculate the intersected permissions. If there are none, return null.
        Dim val As SoundPermissionState = CType(Math.Min(CType(m_flags, Int32), CType(soundPerm.m_flags, Int32)), SoundPermissionState)
        If val = 0 Then
            Return Nothing
        End If
        ' Return a new object with the intersected permission value.
        Return Clone(False, val)

    End Function 'Intersect

    ' Called by the Demand method: returns true if 'this' is a subset of 'target'.
    Public Overrides Function IsSubsetOf(ByVal target As IPermission) As [Boolean]
        ' If 'target' is null and this permission allows nothing, return true.
        If target Is Nothing Then
            Return m_flags = 0
        End If
        ' Both objects must be the same type.
        Dim soundPerm As SoundPermission = VerifyTypeMatch(target)

        ' Return true if the permissions of 'this' is a subset of 'target'.
        Return m_flags <= soundPerm.m_flags

    End Function 'IsSubsetOf

    ' Return a new object that matches 'this' object's permissions.
    Public Overrides Function Copy() As IPermission
        Return CType(Clone(), IPermission)

    End Function 'Copy

    ' Return a new object that contains the union of 'this' and 'target'.
    ' Note: You do not have to implement this method. If you do not, the version
    ' in CodeAccessPermission does this:
    '    1. If target is not null, a NotSupportedException is thrown.
    '    2. If target is null, then Copy is called and the new object is returned.
    Public Overrides Function Union(ByVal target As IPermission) As IPermission
        ' If 'target' is null, then return a copy of 'this'.
        If target Is Nothing Then
            Return Copy()
        End If
        ' Both objects must be the same type.
        Dim soundPerm As SoundPermission = VerifyTypeMatch(target)

        ' If 'this' or 'target' are unrestricted, return a new unrestricted permission.
        If m_specifiedAsUnrestricted OrElse soundPerm.m_specifiedAsUnrestricted Then
            Return Clone(True, SoundPermissionState.PlayAnySound)
        End If
        ' Return a new object with the calculated, unioned permission value.
        Return Clone(False, CType(Math.Max(CType(m_flags, Int32), CType(soundPerm.m_flags, Int32)), SoundPermissionState))

    End Function 'Union
#End Region
#Region "ISecurityEncodable Members"

    ' Populate the permission's fields from XML.
    Public Overrides Sub FromXml(ByVal e As SecurityElement)
        m_specifiedAsUnrestricted = False
        m_flags = 0

        ' If XML indicates an unrestricted permission, make this permission unrestricted.
        Dim s As String = CStr(e.Attributes("Unrestricted"))
        If Not (s Is Nothing) Then
            m_specifiedAsUnrestricted = Convert.ToBoolean(s)
            If m_specifiedAsUnrestricted Then
                m_flags = SoundPermissionState.PlayAnySound
            End If
        End If
        ' If XML indicates a restricted permission, parse the flags.
        If Not m_specifiedAsUnrestricted Then
            s = CStr(e.Attributes("Flags"))
            If Not (s Is Nothing) Then
                m_flags = CType(Convert.ToInt32([Enum].Parse(GetType(SoundPermission), s, True)), SoundPermissionState)
            End If
        End If

    End Sub

    ' Produce XML from the permission's fields.
    Public Overrides Function ToXml() As SecurityElement
        ' These first three lines create an element with the required format.
        Dim e As New SecurityElement("IPermission")
        ' Replace the double quotation marks ("") with single quotation marks ('')
        ' to remain XML compliant when the culture is not neutral.
        e.AddAttribute("class", [GetType]().AssemblyQualifiedName.Replace(ControlChars.Quote, "'"c))
        e.AddAttribute("version", "1")

        If Not m_specifiedAsUnrestricted Then
            e.AddAttribute("Flags", [Enum].Format(GetType(SoundPermissionState), m_flags, "G"))
        Else
            e.AddAttribute("Unrestricted", "true")
        End If
        Return e

    End Function 'ToXml
#End Region
#Region "IUnrestrictedPermission Members"

    ' Returns true if permission is effectively unrestricted.
    Public Function IsUnrestricted() As [Boolean] Implements IUnrestrictedPermission.IsUnrestricted
        ' This means that the object is unrestricted at runtime.
        Return m_flags = SoundPermissionState.PlayAnySound

    End Function 'IsUnrestricted
#End Region
#Region "ICloneable Members"
    ' Return a copy of the permission.
    Public Function Clone() As [Object] Implements System.ICloneable.Clone
        Return MemberwiseClone()

    End Function 'Clone
#End Region

End Class

Комментарии

XML-представление разрешений используется для описания экземпляров разрешений для запросов кода, декларативных наборов разрешений безопасности и конфигурации политики безопасности.

Примечание

Этот интерфейс необходимо реализовать для любого нового объекта разрешений.

Методы

FromXml(SecurityElement)	Восстанавливает объект безопасности с указанным состоянием из кодировки XML.
ToXml()	Создает кодировку XML для объекта безопасности и его текущего состояния.