PermissionSet Class
Represents a collection that can contain many different types of permissions.
Assembly: mscorlib (in mscorlib.dll)
'Declaration <SerializableAttribute> _ <ComVisibleAttribute(True)> _ <StrongNameIdentityPermissionAttribute(SecurityAction.InheritanceDemand, Name := "mscorlib", _ PublicKey := "0x00000000000000000400000000000000")> _ Public Class PermissionSet _ Implements ISecurityEncodable, ICollection, IEnumerable, IStackWalk, _ IDeserializationCallback 'Usage Dim instance As PermissionSet
The following code example demonstrates the use of the PermissionSet class and members.
' This sample demonstrates the use of the PermissionSet class. Imports System Imports System.Reflection Imports System.Security.Permissions Imports System.Security Imports System.IO Imports System.Collections Imports Microsoft.VisualBasic Class [MyClass] Public Shared Sub PermissionSetDemo() Console.WriteLine("Executing PermissionSetDemo") Try ' Open a new PermissionSet. Dim ps1 As New PermissionSet(PermissionState.None) Console.WriteLine("Adding permission to open a file from a file dialog box.") ' Add a permission to the permission set. ps1.AddPermission(New FileDialogPermission(FileDialogPermissionAccess.Open)) Console.WriteLine("Demanding permission to open a file.") ps1.Demand() Console.WriteLine("Demand succeeded.") Console.WriteLine("Adding permission to save a file from a file dialog box.") ps1.AddPermission(New FileDialogPermission(FileDialogPermissionAccess.Save)) Console.WriteLine("Demanding permission to open and save a file.") ps1.Demand() Console.WriteLine("Demand succeeded.") Console.WriteLine("Adding permission to read environment variable USERNAME.") ps1.AddPermission(New EnvironmentPermission(EnvironmentPermissionAccess.Read, "USERNAME")) ps1.Demand() Console.WriteLine("Demand succeeded.") Console.WriteLine("Adding permission to read environment variable COMPUTERNAME.") ps1.AddPermission(New EnvironmentPermission(EnvironmentPermissionAccess.Read, "COMPUTERNAME")) ' Demand all the permissions in the set. Console.WriteLine("Demand all permissions.") ps1.Demand() Console.WriteLine("Demand succeeded.") ' Display the number of permissions in the set. Console.WriteLine("Number of permissions = " & ps1.Count) ' Display the value of the IsSynchronized property. Console.WriteLine("IsSynchronized property = " & ps1.IsSynchronized) ' Display the value of the IsReadOnly property. Console.WriteLine("IsReadOnly property = " & ps1.IsReadOnly) ' Display the value of the SyncRoot property. Console.WriteLine("SyncRoot property = " & CType(ps1.SyncRoot, PermissionSet).ToString()) ' Display the result of a call to the ContainsNonCodeAccessPermissions method. ' Gets a value indicating whether the PermissionSet contains permissions ' that are not derived from CodeAccessPermission. ' Returns true if the PermissionSet contains permissions that are not ' derived from CodeAccessPermission; otherwise, false. Console.WriteLine("ContainsNonCodeAccessPermissions method returned " & ps1.ContainsNonCodeAccessPermissions()) Console.WriteLine("Value of the permission set ToString = " & ControlChars.Lf & ps1.ToString()) Dim ps2 As New PermissionSet(PermissionState.None) ' Create a second permission set and compare it to the first permission set. ps2.AddPermission(New EnvironmentPermission(EnvironmentPermissionAccess.Read, "USERNAME")) ps2.AddPermission(New EnvironmentPermission(EnvironmentPermissionAccess.Write, "COMPUTERNAME")) Console.WriteLine("Permissions in first permission set:") Dim list As IEnumerator = ps1.GetEnumerator() While list.MoveNext() Console.WriteLine(list.Current.ToString()) End While Console.WriteLine("Second permission IsSubsetOf first permission = " & ps2.IsSubsetOf(ps1)) ' Display the intersection of two permission sets. Dim ps3 As PermissionSet = ps2.Intersect(ps1) Console.WriteLine("The intersection of the first permission set and " & "the second permission set = " & ps3.ToString()) ' Create a new permission set. Dim ps4 As New PermissionSet(PermissionState.None) ps4.AddPermission(New FileIOPermission(FileIOPermissionAccess.Read, "C:\Temp\Testfile.txt")) ps4.AddPermission(New FileIOPermission(FileIOPermissionAccess.Read Or FileIOPermissionAccess.Write Or FileIOPermissionAccess.Append, "C:\Temp\Testfile.txt")) ' Display the union of two permission sets. Dim ps5 As PermissionSet = ps3.Union(ps4) Console.WriteLine("The union of permission set 3 and permission set 4 = " & ps5.ToString()) ' Remove FileIOPermission from the permission set. ps5.RemovePermission(GetType(FileIOPermission)) Console.WriteLine("The last permission set after removing FileIOPermission = " & ps5.ToString()) ' Change the permission set using SetPermission. ps5.SetPermission(New EnvironmentPermission(EnvironmentPermissionAccess.AllAccess, "USERNAME")) Console.WriteLine("Permission set after SetPermission = " & ps5.ToString()) ' Display result of ToXml and FromXml operations. Dim ps6 As New PermissionSet(PermissionState.None) ps6.FromXml(ps5.ToXml()) Console.WriteLine("Result of ToFromXml = " & ps6.ToString() & ControlChars.Lf) ' Display results of PermissionSet.GetEnumerator. Dim psEnumerator As IEnumerator = ps1.GetEnumerator() While psEnumerator.MoveNext() Console.WriteLine(psEnumerator.Current) End While ' Check for an unrestricted permission set. Dim ps7 As New PermissionSet(PermissionState.Unrestricted) Console.WriteLine("Permission set is unrestricted = " & ps7.IsUnrestricted()) ' Create and display a copy of a permission set. ps7 = ps5.Copy() Console.WriteLine("Result of copy = " & ps7.ToString()) Catch e As Exception Console.WriteLine(e.Message.ToString()) End Try End Sub 'PermissionSetDemo Overloads Shared Sub Main(ByVal args() As String) PermissionSetDemo() End Sub 'Main End Class '[MyClass]
- StrongNameIdentityPermission
for the ability to inherit from PermissionSet. Only an assembly signed with the Microsoft StrongName can inherit from PermissionSet.
Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98
The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.