CodeAccessPermission Class
Defines the underlying structure of all code access permissions.
Assembly: mscorlib (in mscorlib.dll)
System.Security.CodeAccessPermission
System.Configuration.ConfigurationPermission
System.Data.Common.DBDataPermission
System.Data.OracleClient.OraclePermission
System.Drawing.Printing.PrintingPermission
System.Messaging.MessageQueuePermission
System.Net.DnsPermission
System.Net.Mail.SmtpPermission
System.Net.NetworkInformation.NetworkInformationPermission
System.Net.PeerToPeer.Collaboration.PeerCollaborationPermission
System.Net.PeerToPeer.PnrpPermission
System.Net.SocketPermission
System.Net.WebPermission
System.Security.Permissions.DataProtectionPermission
System.Security.Permissions.EnvironmentPermission
System.Security.Permissions.FileDialogPermission
System.Security.Permissions.FileIOPermission
System.Security.Permissions.GacIdentityPermission
System.Security.Permissions.IsolatedStoragePermission
System.Security.Permissions.KeyContainerPermission
System.Security.Permissions.MediaPermission
System.Security.Permissions.PublisherIdentityPermission
System.Security.Permissions.ReflectionPermission
System.Security.Permissions.RegistryPermission
System.Security.Permissions.ResourcePermissionBase
System.Security.Permissions.SecurityPermission
System.Security.Permissions.SiteIdentityPermission
System.Security.Permissions.StorePermission
System.Security.Permissions.StrongNameIdentityPermission
System.Security.Permissions.TypeDescriptorPermission
System.Security.Permissions.UIPermission
System.Security.Permissions.UrlIdentityPermission
System.Security.Permissions.WebBrowserPermission
System.Security.Permissions.ZoneIdentityPermission
System.Transactions.DistributedTransactionPermission
System.Web.AspNetHostingPermission
System.Xaml.Permissions.XamlLoadPermission
| Name | Description | |
|---|---|---|
![]() | CodeAccessPermission() | Initializes a new instance of the CodeAccessPermission class. |
| Name | Description | |
|---|---|---|
![]() | Assert() | Declares that the calling code can access the resource protected by a permission demand through the code that calls this method, even if callers higher in the stack have not been granted permission to access the resource. Using Assert can create security issues. |
![]() | Copy() | When implemented by a derived class, creates and returns an identical copy of the current permission object. |
![]() | Demand() | Forces a SecurityException at run time if all callers higher in the call stack have not been granted the permission specified by the current instance. |
![]() | Deny() | Obsolete. Prevents callers higher in the call stack from using the code that calls this method to access the resource specified by the current instance. |
![]() | Equals(Object) | Determines whether the specified CodeAccessPermission object is equal to the current CodeAccessPermission.(Overrides Object.Equals(Object).) |
![]() | Finalize() | Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection.(Inherited from Object.) |
![]() | FromXml(SecurityElement) | When overridden in a derived class, reconstructs a security object with a specified state from an XML encoding. |
![]() | GetHashCode() | Gets a hash code for the CodeAccessPermission object that is suitable for use in hashing algorithms and data structures such as a hash table.(Overrides Object.GetHashCode().) |
![]() | GetType() | |
![]() | Intersect(IPermission) | When implemented by a derived class, creates and returns a permission that is the intersection of the current permission and the specified permission. |
![]() | IsSubsetOf(IPermission) | When implemented by a derived class, determines whether the current permission is a subset of the specified permission. |
![]() | MemberwiseClone() | |
![]() | PermitOnly() | Prevents callers higher in the call stack from using the code that calls this method to access all resources except for the resource specified by the current instance. |
![]() ![]() | RevertAll() | Causes all previous overrides for the current frame to be removed and no longer in effect. |
![]() ![]() | RevertAssert() | Causes any previous Assert for the current frame to be removed and no longer in effect. |
![]() ![]() | RevertDeny() | Obsolete. Causes any previous Deny for the current frame to be removed and no longer in effect. |
![]() ![]() | RevertPermitOnly() | Causes any previous PermitOnly for the current frame to be removed and no longer in effect. |
![]() | ToString() | Creates and returns a string representation of the current permission object.(Overrides Object.ToString().) |
![]() | ToXml() | When overridden in a derived class, creates an XML encoding of the security object and its current state. |
![]() | Union(IPermission) | When overridden in a derived class, creates a permission that is the union of the current permission and the specified permission. |
Code access permissions use a stack walk to ensure that all callers of the code have been granted a permission. If a permission object is null, it is handled the same as a permission object with the state PermissionState.None.
The call stack is typically represented as growing down, so that methods higher in the call stack call methods lower in the call stack.
Inheritors of the CodeAccessPermission class must be granted full trust to function correctly as permissions extending the security infrastructure. To determine that the inheritors are fully trusted, CodeAccessPermission issues an InheritanceDemand for ControlEvidence = true and ControlPolicy = true.
Notes to Inheritors:
When you inherit from CodeAccessPermission, you must also implement the IUnrestrictedPermission interface.
The following CodeAccessPermission members must be overridden: Copy, Intersect, IsSubsetOf, ToXml, FromXml, and Union.
You must also define a constructor that takes a PermissionState as its only parameter.
You must apply the SerializableAttribute attribute to a class that inherits from CodeAccessPermission.
The following code example shows a permission derived from the CodeAccessPermission class.
' This custom permission is intended only for the purposes of illustration. ' The following code shows how to create a custom permission that inherits ' from CodeAccessPermission. The code implements all required overrides. ' A wildcard character ('*') is implemented for the Name property. Imports System Imports System.Security Imports System.Security.Permissions Imports System.IO Imports System.Security.Policy Imports System.Collections Imports Microsoft.VisualBasic <assembly: System.Reflection.AssemblyKeyFile("Key.snk")> <assembly: System.Security.AllowPartiallyTrustedCallersAttribute()> Namespace MyPermission <Serializable()> _ Public NotInheritable Class NameIdPermission Inherits CodeAccessPermission Implements IUnrestrictedPermission Private m_Name As String Private m_Unrestricted As Boolean Public Sub New(ByVal name As String) m_name = name End Sub 'NewNew Public Sub New(ByVal state As PermissionState) If state = PermissionState.None Then m_name = "" ElseIf state = PermissionState.Unrestricted Then Throw New ArgumentException("Unrestricted state is not allowed for identity permissions.") Else Throw New ArgumentException("Invalid permission state.") End If End Sub 'New Public Property Name() As String Get Return m_name End Get Set(ByVal Value As String) m_name = Value End Set End Property Public Overrides Function Copy() As IPermission Dim name As String name = m_name Return New NameIdPermission(name) End Function 'Copy Public Function IsUnrestricted() As Boolean Implements IUnrestrictedPermission.IsUnrestricted ' Always false, unrestricted state is not allowed. Return m_Unrestricted End Function Private Function VerifyType(ByVal target As IPermission) As Boolean Return TypeOf target Is NameIdPermission End Function 'VerifyType Public Overrides Function IsSubsetOf(ByVal target As IPermission) As Boolean #If (Debug) Then Console.WriteLine("************* Entering IsSubsetOf *********************") #End If If target Is Nothing Then Console.WriteLine("IsSubsetOf: target == null") Return False End If #If (Debug) Then Console.WriteLine(("This is = " + CType(Me, NameIdPermission).Name)) Console.WriteLine(("Target is " + CType(target, NameIdPermission).m_name)) #End If Try Dim operand As NameIdPermission = CType(target, NameIdPermission) ' The following check for unrestricted permission is only included as an example for ' permissions that allow the unrestricted state. It is of no value for this permission. If True = operand.m_Unrestricted Then Return True ElseIf True = Me.m_Unrestricted Then Return False End If If Not (Me.m_name Is Nothing) Then If operand.m_name Is Nothing Then Return False End If If Me.m_name = "" Then Return True End If End If If Me.m_name.Equals(operand.m_name) Then Return True Else ' Check for wild card character '*'. Dim i As Integer = operand.m_name.LastIndexOf("*") If i > 0 Then Dim prefix As String = operand.m_name.Substring(0, i) If Me.m_name.StartsWith(prefix) Then Return True End If End If End If Return False Catch Throw New ArgumentException(String.Format("Argument_WrongType", Me.GetType().FullName)) End Try End Function Public Overrides Function Intersect(ByVal target As IPermission) As IPermission Console.WriteLine("************* Entering Intersect *********************") If target Is Nothing Then Return Nothing End If #If (Debug) Then Console.WriteLine(("This is = " + CType(Me, NameIdPermission).Name)) Console.WriteLine(("Target is " + CType(target, NameIdPermission).m_name)) #End If If Not VerifyType(target) Then Throw New ArgumentException(String.Format("Argument is wrong type.", Me.GetType().FullName)) End If Dim operand As NameIdPermission = CType(target, NameIdPermission) If operand.IsSubsetOf(Me) Then Return operand.Copy() ElseIf Me.IsSubsetOf(operand) Then Return Me.Copy() Else Return Nothing End If End Function 'Intersect Public Overrides Function Union(ByVal target As IPermission) As IPermission #If (Debug) Then Console.WriteLine("************* Entering Union *********************") #End If If target Is Nothing Then Return Me End If #If (Debug) Then Console.WriteLine(("This is = " + CType(Me, NameIdPermission).Name)) Console.WriteLine(("Target is " + CType(target, NameIdPermission).m_name)) #End If If Not VerifyType(target) Then Throw New ArgumentException(String.Format("Argument_WrongType", Me.GetType().FullName)) End If Dim operand As NameIdPermission = CType(target, NameIdPermission) If operand.IsSubsetOf(Me) Then Return Me.Copy() ElseIf Me.IsSubsetOf(operand) Then Return operand.Copy() Else Return Nothing End If End Function 'Union Public Overrides Sub FromXml(ByVal e As SecurityElement) ' The following code for unrestricted permission is only included as an example for ' permissions that allow the unrestricted state. It is of no value for this permission. Dim elUnrestricted As String = e.Attribute("Unrestricted") If Nothing <> elUnrestricted Then m_Unrestricted = Boolean.Parse(elUnrestricted) Return End If Dim elName As String = e.Attribute("Name") m_name = IIf(elName Is Nothing, Nothing, elName) End Sub 'FromXml Public Overrides Function ToXml() As SecurityElement ' Use the SecurityElement class to encode the permission to XML. Dim esd As New SecurityElement("IPermission") Dim name As String = GetType(NameIdPermission).AssemblyQualifiedName esd.AddAttribute("class", name) esd.AddAttribute("version", "1.0") ' The following code for unrestricted permission is only included as an example for ' permissions that allow the unrestricted state. It is of no value for this permission. If m_Unrestricted Then esd.AddAttribute("Unrestricted", True.ToString()) End If If Not (m_Name Is Nothing) Then esd.AddAttribute("Name", m_Name) End If Return esd End Function 'ToXml End Class ' NameIdPermission End Namespace
for the ability of inheritors to provide evidence and view and modify policy. Associated enumerations: SecurityPermissionFlag.ControlEvidence, SecurityPermissionFlag.ControlPolicy.
Available since 1.1
Any public static ( Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.


