FileCodeGroup Class

Definition

Namespace:

System.Security.Policy

Assembly:

System.Security.Permissions.dll

Source:

FileCodeGroup.cs

Caution

Code Access Security is not supported or honored by the runtime.

Grants permission to manipulate files located in the code assemblies to code assemblies that match the membership condition. This class cannot be inherited.

public ref class FileCodeGroup sealed : System::Security::Policy::CodeGroup

[System.Obsolete("Code Access Security is not supported or honored by the runtime.", DiagnosticId="SYSLIB0003", UrlFormat="https://aka.ms/dotnet-warnings/{0}")]
public sealed class FileCodeGroup : System.Security.Policy.CodeGroup

[<System.Obsolete("Code Access Security is not supported or honored by the runtime.", DiagnosticId="SYSLIB0003", UrlFormat="https://aka.ms/dotnet-warnings/{0}")>]
type FileCodeGroup = class
    inherit CodeGroup

Public NotInheritable Class FileCodeGroup
Inherits CodeGroup

Inheritance

Object

CodeGroup

FileCodeGroup

Attributes

ObsoleteAttribute

Examples

The following example shows the use of members of the FileCodeGroup class.

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

ref class Members
{
public:
   [STAThread]
   static void Main()
   {
      FileCodeGroup^ fileCodeGroup = constructDefaultGroup();
      
      // Create a deep copy of the FileCodeGroup.
      FileCodeGroup^ copyCodeGroup =
         dynamic_cast<FileCodeGroup^>(fileCodeGroup->Copy());

      CompareTwoCodeGroups( fileCodeGroup, copyCodeGroup );
      addPolicy(  &fileCodeGroup );
      addXmlMember(  &fileCodeGroup );
      updateMembershipCondition(  &fileCodeGroup );
      addChildCodeGroup(  &fileCodeGroup );
      Console::Write( L"Comparing the resolved code group " );
      Console::WriteLine( L"with the initial code group." );
      FileCodeGroup^ resolvedCodeGroup =
         ResolveGroupToEvidence( fileCodeGroup );
      if ( CompareTwoCodeGroups( fileCodeGroup, resolvedCodeGroup ) )
      {
         PrintCodeGroup( resolvedCodeGroup );
      }
      else
      {
         PrintCodeGroup( fileCodeGroup );
      }

      Console::WriteLine( L"This sample completed successfully; press Enter to exit." );
      Console::ReadLine();
   }

private:
   // Construct a new FileCodeGroup with Read, Write, Append
   // and PathDiscovery access.
   static FileCodeGroup^ constructDefaultGroup()
   {
      // Construct a new file code group that has complete access to
      // files in the specified path.
      FileCodeGroup^ fileCodeGroup = gcnew FileCodeGroup(
         gcnew AllMembershipCondition,FileIOPermissionAccess::AllAccess );

      // Set the name of the file code group.
      fileCodeGroup->Name = L"TempCodeGroup";

      // Set the description of the file code group.
      fileCodeGroup->Description = L"Temp folder permissions group";

      // Retrieve the string representation of the  fileCodeGroup�s
      // attributes. FileCodeGroup does not use AttributeString, so the
      // value should be null.
      if ( fileCodeGroup->AttributeString != nullptr )
      {
         throw gcnew NullReferenceException(
            L"The AttributeString property should be null." );
      }

      return fileCodeGroup;
   }

   // Add file permission to restrict write access to all files on the
   // local machine.
   static void addPolicy( interior_ptr<FileCodeGroup^> fileCodeGroup )
   {
      // Set the PolicyStatement property to a policy with read access to
      // the root directory of drive C.
      FileIOPermission^ rootFilePermissions =
         gcnew FileIOPermission( PermissionState::None );
      rootFilePermissions->AllLocalFiles =
         FileIOPermissionAccess::Read;
      rootFilePermissions->SetPathList(
         FileIOPermissionAccess::Read, L"C:\\" );
      NamedPermissionSet^ namedPermissions =
         gcnew NamedPermissionSet( L"RootPermissions" );
      namedPermissions->AddPermission( rootFilePermissions );
      ( *fileCodeGroup )->PolicyStatement =
         gcnew PolicyStatement( namedPermissions );
   }

   // Set the membership condition of the specified FileCodeGroup
   // to the Intranet zone.
   static void updateMembershipCondition( interior_ptr<FileCodeGroup^> fileCodeGroup )
   {
      ZoneMembershipCondition^ zoneCondition =
         gcnew ZoneMembershipCondition( SecurityZone::Intranet );
      ( *fileCodeGroup )->MembershipCondition = zoneCondition;
   }

   // Add a child group with read-access file permission to the specified
   // code group.
   static void addChildCodeGroup( interior_ptr<FileCodeGroup^> fileCodeGroup )
   {
      // Create a file code group with read-access permission.
      FileCodeGroup^ tempFolderCodeGroup = gcnew FileCodeGroup(
         gcnew AllMembershipCondition,FileIOPermissionAccess::Read );
      
      // Set the name of the child code group and add it to
      // the specified code group.
      tempFolderCodeGroup->Name = L"Read-only group";
      ( *fileCodeGroup )->AddChild( tempFolderCodeGroup );
   }

   // Compare the two specified file code groups for equality.
   static bool CompareTwoCodeGroups( FileCodeGroup^ firstCodeGroup,
      FileCodeGroup^ secondCodeGroup )
   {
      if ( firstCodeGroup->Equals( secondCodeGroup ) )
      {
         Console::WriteLine( L"The two code groups are equal." );
         return true;
      }
      else
      {
         Console::WriteLine( L"The two code groups are not equal." );
         return false;
      }
   }

   // Retrieve the resolved policy based on Evidence from the executing
   // assembly found in the specified code group.
   static String^ ResolveEvidence( CodeGroup^ fileCodeGroup )
   {
      String^ policyString = L"";
      
      // Resolve the policy based on evidence in the executing assembly.
      Assembly^ assembly = Members::typeid->Assembly;
      Evidence^ executingEvidence = assembly->Evidence;
      PolicyStatement^ policy = fileCodeGroup->Resolve( executingEvidence );

      if ( policy != nullptr )
      {
         policyString = policy->ToString();
      }

      return policyString;
   }

   // Retrieve the resolved code group based on the Evidence from
   // the executing assembly found in the specified code group.
   static FileCodeGroup^ ResolveGroupToEvidence( FileCodeGroup^ fileCodeGroup )
   {
      // Resolve matching code groups to the executing assembly.
      Assembly^ assembly = Members::typeid->Assembly;
      Evidence^ evidence = assembly->Evidence;
      CodeGroup^ codeGroup = fileCodeGroup->ResolveMatchingCodeGroups( evidence );

      return dynamic_cast<FileCodeGroup^>(codeGroup);
   }

   // If a domain attribute is not found in the specified FileCodeGroup,
   // add a child XML element identifying a custom membership condition.
   static void addXmlMember( interior_ptr<FileCodeGroup^> fileCodeGroup )
   {
      SecurityElement^ xmlElement = ( *fileCodeGroup )->ToXml();

      SecurityElement^ rootElement = gcnew SecurityElement( L"CodeGroup" );
      if ( xmlElement->Attribute(L"domain") == nullptr )
      {
         SecurityElement^ newElement = gcnew SecurityElement(
            L"CustomMembershipCondition" );
         newElement->AddAttribute( L"class", L"CustomMembershipCondition" );
         newElement->AddAttribute( L"version", L"1" );
         newElement->AddAttribute( L"domain", L"contoso.com" );
         rootElement->AddChild( newElement );
         ( *fileCodeGroup )->FromXml( rootElement );
      }

      Console::WriteLine( L"Added a custom membership condition:" );
      Console::WriteLine( rootElement );
   }

   // Print the properties of the specified code group to the console.
   static void PrintCodeGroup( CodeGroup^ codeGroup )
   {
      // Compare the type of the specified object with the FileCodeGroup
      // type.
      if (  !codeGroup->GetType()->Equals( FileCodeGroup::typeid ) )
      {
         throw gcnew ArgumentException( L"Expected the FileCodeGroup type." );
      }

      String^ codeGroupName = codeGroup->Name;
      String^ membershipCondition = codeGroup->MembershipCondition->ToString();
      
      String^ permissionSetName = codeGroup->PermissionSetName;

      int hashCode = codeGroup->GetHashCode();

      String^ mergeLogic = L"";
      
      if ( codeGroup->MergeLogic->Equals( L"Union" ) )
      {
         mergeLogic = L" with Union merge logic";
      }
      
      // Retrieve the class path for FileCodeGroup.
      String^ fileGroupClass = codeGroup->ToString();
      
      // Write summary to the console window.
      Console::WriteLine( L"\n*** {0} summary ***", fileGroupClass );
      Console::Write( L"A FileCodeGroup named " );
      Console::Write( L"{0}{1}", codeGroupName, mergeLogic );
      Console::Write( L" has been created with hash code{0}.", hashCode );
      Console::Write( L"This code group contains a {0}", membershipCondition );
      Console::Write( L" membership condition with the " );
      Console::Write( L"{0} permission set. ", permissionSetName );
      Console::Write( L"The code group has the following security policy: " );
      Console::WriteLine( ResolveEvidence( codeGroup ) );
      int childCount = codeGroup->Children->Count;
      if ( childCount > 0 )
      {
         Console::Write( L"There are {0}", childCount );
         Console::WriteLine( L" child code groups in this code group." );
         
         // Iterate through the child code groups to display their names
         // and remove them from the specified code group.
         for ( int i = 0; i < childCount; i++ )
         {
            // Get child code group as type FileCodeGroup.
            FileCodeGroup^ childCodeGroup =
               dynamic_cast<FileCodeGroup^>(codeGroup->Children->default[ i ]);
            
            Console::Write( L"Removing the {0}.", childCodeGroup->Name );
            // Remove child code group.

            codeGroup->RemoveChild( childCodeGroup );
         }
         Console::WriteLine();
      }
      else
      {
         Console::Write( L"There are no child code groups" );
         Console::WriteLine( L" in this code group." );
      }
   }
};

int main()
{
   Members::Main();
}

//
// This sample produces the following output:
//
// The two code groups are equal.
// Added a custom membership condition:
// <CustomMembershipCondition class="CustomMembershipCondition"
//                                version="1"
//                                domain="contoso.com"/>
// Comparing the resolved code group with the initial code group.
// The two code groups are not equal.
//
// *** System.Security.Policy.FileCodeGroup summary ***
// A FileCodeGroup named  with Union merge logic has been created with hash
// code 113151473. This code group contains a Zone - Intranet membership
// condition with the Same directory FileIO - NoAccess permission set. The
// code group has the following security policy:
// There are 1 child code groups in this code group.
// Removing the Read-only group.
// This sample completed successfully; press Enter to exit.

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

class Members
{
    [STAThread]
    static void Main(string[] args)
    {
        FileCodeGroup fileCodeGroup = constructDefaultGroup();
        
        // Create a deep copy of the FileCodeGroup.
        FileCodeGroup copyCodeGroup = (FileCodeGroup)fileCodeGroup.Copy();

        CompareTwoCodeGroups(fileCodeGroup, copyCodeGroup);

        addPolicy(ref fileCodeGroup);
        addXmlMember(ref fileCodeGroup);
        updateMembershipCondition(ref fileCodeGroup);
        addChildCodeGroup(ref fileCodeGroup);

        Console.Write("Comparing the resolved code group ");
        Console.WriteLine("with the initial code group.");
        FileCodeGroup resolvedCodeGroup =
            ResolveGroupToEvidence(fileCodeGroup);
        if (CompareTwoCodeGroups(fileCodeGroup, resolvedCodeGroup))
        {
            PrintCodeGroup(resolvedCodeGroup);
        }
        else
        {
            PrintCodeGroup(fileCodeGroup);
        }
        
        Console.WriteLine("This sample completed successfully; " +
            "press Enter to exit.");
        Console.ReadLine();
    }

    // Construct a new FileCodeGroup with Read, Write, Append 
    // and PathDiscovery access.
    private static FileCodeGroup constructDefaultGroup()
    {
        // Construct a new file code group that has complete access to
        // files in the specified path.
        FileCodeGroup fileCodeGroup = 
            new FileCodeGroup(
            new AllMembershipCondition(),
            FileIOPermissionAccess.AllAccess);

        // Set the name of the file code group.
        fileCodeGroup.Name = "TempCodeGroup";

        // Set the description of the file code group.
        fileCodeGroup.Description = "Temp folder permissions group";

        // Retrieve the string representation of the  fileCodeGroup’s 
        // attributes. FileCodeGroup does not use AttributeString, so the
        // value should be null.
        if (fileCodeGroup.AttributeString != null)
        {
            throw new NullReferenceException(
                "The AttributeString property should be null.");
        }

        return fileCodeGroup;
    }

    // Add file permission to restrict write access to all files on the
    // local machine.
    private static void addPolicy(ref FileCodeGroup fileCodeGroup)
    {
        // Set the PolicyStatement property to a policy with read access to
        // the root directory of drive C.
        FileIOPermission rootFilePermissions = 
            new FileIOPermission(PermissionState.None);
        rootFilePermissions.AllLocalFiles = FileIOPermissionAccess.Read;
        rootFilePermissions.SetPathList(FileIOPermissionAccess.Read,"C:\\");

        NamedPermissionSet namedPermissions =
            new NamedPermissionSet("RootPermissions");
        namedPermissions.AddPermission(rootFilePermissions);
        
        fileCodeGroup.PolicyStatement =
            new PolicyStatement(namedPermissions);
    }

    // Set the membership condition of the specified FileCodeGroup 
    // to the Intranet zone.
    private static void updateMembershipCondition(
        ref FileCodeGroup fileCodeGroup)
    {
        ZoneMembershipCondition zoneCondition =
            new ZoneMembershipCondition(SecurityZone.Intranet);
        fileCodeGroup.MembershipCondition = zoneCondition;
    }

    // Add a child group with read-access file permission to the specified 
    // code group.
    private static void addChildCodeGroup(ref FileCodeGroup fileCodeGroup)
    {
        // Create a file code group with read-access permission.
        FileCodeGroup tempFolderCodeGroup = new FileCodeGroup(
            new AllMembershipCondition(), 
            FileIOPermissionAccess.Read);

        // Set the name of the child code group and add it to 
        // the specified code group.
        tempFolderCodeGroup.Name = "Read-only group";
        fileCodeGroup.AddChild(tempFolderCodeGroup);
    }

    // Compare the two specified file code groups for equality.
    private static bool CompareTwoCodeGroups(
        FileCodeGroup firstCodeGroup, FileCodeGroup secondCodeGroup)
    {
        if (firstCodeGroup.Equals(secondCodeGroup))
        {
            Console.WriteLine("The two code groups are equal.");
            return true;
        }
        else 
        {
            Console.WriteLine("The two code groups are not equal.");
            return false;
        }
    }

    // Retrieve the resolved policy based on Evidence from the executing 
    // assembly found in the specified code group.
    private static string ResolveEvidence(CodeGroup fileCodeGroup)
    {
        string policyString = "";

        // Resolve the policy based on evidence in the executing assembly.
        Assembly assembly = typeof(Members).Assembly;
        Evidence executingEvidence = assembly.Evidence;

        PolicyStatement policy = fileCodeGroup.Resolve(executingEvidence);

        if (policy != null)
        {
            policyString = policy.ToString();
        }

        return policyString;
    }

    // Retrieve the resolved code group based on the Evidence from 
    // the executing assembly found in the specified code group.
    private static FileCodeGroup ResolveGroupToEvidence(
        FileCodeGroup fileCodeGroup)
    {
        // Resolve matching code groups to the executing assembly.
        Assembly assembly = typeof(Members).Assembly;
        Evidence evidence = assembly.Evidence;
        CodeGroup codeGroup = 
            fileCodeGroup.ResolveMatchingCodeGroups(evidence);

        return (FileCodeGroup)codeGroup;
    }

    // If a domain attribute is not found in the specified FileCodeGroup,
    // add a child XML element identifying a custom membership condition.
    private static void addXmlMember(ref FileCodeGroup fileCodeGroup)
    {
        SecurityElement xmlElement = fileCodeGroup.ToXml();

        SecurityElement rootElement = new SecurityElement("CodeGroup");

        if (xmlElement.Attribute("domain") == null) 
        {
            SecurityElement newElement = 
                new SecurityElement("CustomMembershipCondition");
            newElement.AddAttribute("class","CustomMembershipCondition");
            newElement.AddAttribute("version","1");
            newElement.AddAttribute("domain","contoso.com");

            rootElement.AddChild(newElement);

            fileCodeGroup.FromXml(rootElement);
        }

        Console.WriteLine("Added a custom membership condition:");
        Console.WriteLine(rootElement.ToString());
    }

    // Print the properties of the specified code group to the console.
    private static void PrintCodeGroup(CodeGroup codeGroup)
    {
        // Compare the type of the specified object with the FileCodeGroup
        // type.
        if (!codeGroup.GetType().Equals(typeof(FileCodeGroup)))
        {
            throw new ArgumentException("Expected the FileCodeGroup type.");
        }
        
        string codeGroupName = codeGroup.Name;
        string membershipCondition = codeGroup.MembershipCondition.ToString();
        string permissionSetName = codeGroup.PermissionSetName;

        int hashCode = codeGroup.GetHashCode();

        string mergeLogic = "";
        if (codeGroup.MergeLogic.Equals("Union"))
        {
            mergeLogic = " with Union merge logic";
        }

        // Retrieve the class path for FileCodeGroup.
        string fileGroupClass = codeGroup.ToString();

        // Write summary to the console window.
        Console.WriteLine("\n*** " + fileGroupClass + " summary ***");
        Console.Write("A FileCodeGroup named ");
        Console.Write(codeGroupName + mergeLogic);
        Console.Write(" has been created with hash code" + hashCode + ".");
        Console.Write("This code group contains a " + membershipCondition);
        Console.Write(" membership condition with the ");
        Console.Write(permissionSetName + " permission set. ");

        Console.Write("The code group has the following security policy: ");
        Console.WriteLine(ResolveEvidence(codeGroup));

        int childCount = codeGroup.Children.Count;
        if (childCount > 0 )
        {
            Console.Write("There are " + childCount);
            Console.WriteLine(" child code groups in this code group.");

            // Iterate through the child code groups to display their names
            // and remove them from the specified code group.
            for (int i=0; i < childCount; i++)
            {
                // Get child code group as type FileCodeGroup.
                FileCodeGroup childCodeGroup = 
                    (FileCodeGroup)codeGroup.Children[i];
                
                Console.Write("Removing the " + childCodeGroup.Name + ".");
                // Remove child code group.
                codeGroup.RemoveChild(childCodeGroup);
            }

            Console.WriteLine();
        }
        else
        {
            Console.Write("There are no child code groups");
            Console.WriteLine(" in this code group.");
        }
    }
}
//
// This sample produces the following output:
//
// The two code groups are equal.
// Added a custom membership condition:
// <CustomMembershipCondition class="CustomMembershipCondition"
//                                version="1"
//                                domain="contoso.com"/>
// Comparing the resolved code group with the initial code group.
// The two code groups are not equal.
// 
// *** System.Security.Policy.FileCodeGroup summary ***
// A FileCodeGroup named  with Union merge logic has been created with hash
// code 113151473. This code group contains a Zone - Intranet membership
// condition with the Same directory FileIO - NoAccess permission set. The
// code group has the following security policy:
// There are 1 child code groups in this code group.
// Removing the Read-only group.
// This sample completed successfully; press Enter to exit.

Imports System.Security
Imports System.Security.Policy
Imports System.Security.Permissions
Imports System.Reflection
Imports System.Windows.Forms

Public Class Form1
    Inherits System.Windows.Forms.Form

    ' Event handler for Run button.
    Private Sub Button1_Click( _
        ByVal sender As System.Object, _
        ByVal e As System.EventArgs) Handles Button1.Click

        tbxOutput.Cursor = Cursors.WaitCursor
        tbxOutput.Text = ""

        Dim fileCodeGroup As FileCodeGroup = constructDefaultGroup()

        ' Create a deep copy of the FileCodeGroup;
        Dim copyCodeGroup As FileCodeGroup = _
            CType(fileCodeGroup.Copy(), FileCodeGroup)

        CompareTwoCodeGroups(fileCodeGroup, copyCodeGroup)

        addPolicy(fileCodeGroup)
        addXmlMember(fileCodeGroup)
        updateMembershipCondition(fileCodeGroup)
        addChildCodeGroup(fileCodeGroup)

        WriteLine("Comparing the resolved code group with the initial " + _
            "code group:")
        Dim resolvedCodeGroup As FileCodeGroup
        resolvedCodeGroup = ResolveGroupToEvidence(fileCodeGroup)

        If (CompareTwoCodeGroups(fileCodeGroup, resolvedCodeGroup)) Then
            PrintCodeGroup(resolvedCodeGroup)
        Else
            PrintCodeGroup(fileCodeGroup)
        End If

        ' Reset the cursor and conclude application.
        tbxOutput.AppendText(vbCrLf + "This sample completed " + _
            "successfully; press Exit to continue.")
        tbxOutput.Cursor = Cursors.Default
    End Sub
    ' Construct a new FileCodeGroup with read, write, append and 
    ' discovery access.
    Private Function constructDefaultGroup() As FileCodeGroup
        ' Construct a file code group with read, write, append and 
        ' discovery access.
        Dim fileCodeGroup As New FileCodeGroup( _
            New AllMembershipCondition, _
            FileIOPermissionAccess.AllAccess)

        ' Set the name of the file code group.
        fileCodeGroup.Name = "TempCodeGroup"

        ' Set the description of the file code group.
        fileCodeGroup.Description = "Temp folder permissions group"

        ' Retrieve the string representation of the Policy's attributes.
        ' FileCodeGroup does not use AttributeString, so the value should
        ' be null.
        If (Not fileCodeGroup.AttributeString Is Nothing) Then
            Throw New NullReferenceException( _
                "AttributeString property is not empty")
        End If

        Return fileCodeGroup
    End Function

    ' Add file permission to restrict write access to all files on the 
    ' local machine.
    Private Sub addPolicy(ByRef fileCodeGroup As FileCodeGroup)
        ' Set the PolicyStatement property to a policy with
        ' read access to c:\.
        Dim rootFilePermissions As New FileIOPermission(PermissionState.None)
        rootFilePermissions.AllLocalFiles = FileIOPermissionAccess.Read
        rootFilePermissions.SetPathList(FileIOPermissionAccess.Read, "C:\\")

        Dim namedPermissions As New NamedPermissionSet("RootPermissions")
        namedPermissions.AddPermission(rootFilePermissions)

        fileCodeGroup.PolicyStatement = New PolicyStatement(namedPermissions)
    End Sub

    ' Set the membership condition of the specified FileCodeGroup to 
    ' Intranet zone.
    Private Sub updateMembershipCondition( _
        ByRef fileCodeGroup As FileCodeGroup)

        ' Set the membership condition to the Intranet zone.
        Dim zoneCondition As _
            New ZoneMembershipCondition(SecurityZone.Intranet)

        fileCodeGroup.MembershipCondition = zoneCondition
    End Sub

    ' Add a child group with read-access file permissions to the specified
    ' code group.
    Private Sub addChildCodeGroup(ByRef fileCodeGroup As FileCodeGroup)
        ' Create a file code group with read access.
        Dim tempFolderCodeGroup As New FileCodeGroup( _
            New AllMembershipCondition, _
            FileIOPermissionAccess.Read)

        ' Set the name of the child code group and add it to the specified 
        ' code group.
        tempFolderCodeGroup.Name = "Read-only group"
        fileCodeGroup.AddChild(tempFolderCodeGroup)
    End Sub

    ' Compare two specified FileCodeGroups for equality.
    Private Function CompareTwoCodeGroups( _
        ByVal firstCodeGroup As FileCodeGroup, _
        ByVal secondCodeGroup As FileCodeGroup) As Boolean

        ' Compare two FileCodeGroups for equality.
        If (firstCodeGroup.Equals(secondCodeGroup)) Then
            WriteLine("The two code groups are equal.")
            Return True
        Else
            WriteLine("The two code groups are not equal.")
            Return False
        End If

    End Function

    ' Retrieve the resolved policy based on the executing evidence found 
    ' in the specified code group.
    Private Function ResolveEvidence( _
        ByVal fileCodeGroup As CodeGroup) As String

        Dim policyString As String = ""

        ' Resolve the policy based on the executing assemlby's evidence.
        Dim executingAssembly As [Assembly]
        executingAssembly = Me.GetType().Assembly

        Dim executingEvidence As Evidence = executingAssembly.Evidence

        Dim policy As PolicyStatement
        policy = fileCodeGroup.Resolve(executingEvidence)

        If (Not policy Is Nothing) Then
            policyString = policy.ToString()
        End If

        Return policyString
    End Function

    ' Retrieve the resolved code group based on the executing evidence found
    ' in the specified code group.
    Private Function ResolveGroupToEvidence( _
        ByVal fileCodeGroup As FileCodeGroup) As FileCodeGroup

        ' Resolve matching code groups to the executing assembly.
        Dim executingAssembly As [Assembly]
        executingAssembly = Me.GetType().Assembly

        Dim evidence As Evidence = executingAssembly.Evidence

        Dim codeGroup As CodeGroup
        codeGroup = fileCodeGroup.ResolveMatchingCodeGroups(evidence)

        Return CType(codeGroup, FileCodeGroup)
    End Function

    ' If domain attribute is not found in specified FileCodeGroup, 
    ' add a child Xml element identifying a custom membership condition.
    Private Sub addXmlMember(ByRef fileCodeGroup As FileCodeGroup)
        Dim xmlElement As SecurityElement = fileCodeGroup.ToXml()

        Dim rootElement As New SecurityElement("CodeGroup")
        If (xmlElement.Attribute("domain") Is Nothing) Then
            Dim newElement As New SecurityElement("CustomMembershipCondition")
            newElement.AddAttribute("class", "CustomMembershipCondition")
            newElement.AddAttribute("version", "1")
            newElement.AddAttribute("domain", "contoso.com")

            rootElement.AddChild(newElement)

            fileCodeGroup.FromXml(rootElement)

        End If

        WriteLine("Added a custom membership condition:")
        WriteLine(rootElement.ToString())
    End Sub

    ' Print the properties of the specified code group to the output textbox.
    Private Sub PrintCodeGroup(ByVal codeGroup As CodeGroup)
        ' Compare specified object's type with the FileCodeGroup type.
        If (Not codeGroup.GetType() Is GetType(FileCodeGroup)) Then
            Throw New ArgumentException("Excepted FileCodeGroup type")
        End If

        Dim codeGroupName As String = codeGroup.Name
        Dim membershipCondition As String
        membershipCondition = codeGroup.MembershipCondition.ToString()

        Dim permissionSetName As String = codeGroup.PermissionSetName

        Dim hashCode As Integer = codeGroup.GetHashCode()

        Dim mergeLogic As String = ""
        If (codeGroup.MergeLogic.Equals("Union")) Then
            mergeLogic = " with Union merge logic"
        End If

        ' Retrieve the class path for FileCodeGroup.
        Dim fileGroupClass As String = codeGroup.ToString()

        ' Write summary to console window.
        WriteLine(vbCrLf + "*** " + fileGroupClass + " summary ***")
        Write("A FileCodeGroup named " + codeGroupName + mergeLogic)
        Write(" has been created with hash code(" + hashCode.ToString())
        Write("). It contains a " + membershipCondition)
        Write(" membership condition with the ")
        Write(permissionSetName + " permission set. ")

        WriteLine("It has the following policy: " + _
            ResolveEvidence(codeGroup))
        Dim childCount As Integer = codeGroup.Children.Count
        If (childCount > 0) Then
            Write("There are " + childCount.ToString())
            WriteLine(" child elements in the code group:")

            ' Iterate through the child code groups to display their names and
            '  remove them from the specified code group.
            For i As Int16 = 0 To childCount - 1 Step 1
                ' Get child code group as type FileCodeGroup.
                Dim childCodeGroup As FileCodeGroup
                childCodeGroup = CType(codeGroup.Children(i), FileCodeGroup)

                Write("Removing the " + childCodeGroup.Name + ".")
                ' Remove child codegroup.
                codeGroup.RemoveChild(childCodeGroup)
            Next

            WriteLine("")

        Else
            WriteLine("There are no children found in the code group:")

        End If
    End Sub
    ' Write message to the output textbox.
    Private Sub Write(ByVal message As String)
        tbxOutput.AppendText(message)

    End Sub
    ' Write message with carriage return to the output textbox.
    Private Sub WriteLine(ByVal message As String)
        tbxOutput.AppendText(message + vbCrLf)

    End Sub


    ' Event handler for Exit button.
    Private Sub Button2_Click( _
        ByVal sender As System.Object, _
        ByVal e As System.EventArgs) Handles Button2.Click

        Application.Exit()
    End Sub
#Region " Windows Form Designer generated code "

    Public Sub New()
        MyBase.New()

        'This call is required by the Windows Form Designer.
        InitializeComponent()

        'Add any initialization after the InitializeComponent() call

    End Sub

    'Form overrides dispose to clean up the component list.
    Protected Overloads Overrides 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 by the Windows Form Designer
    Private components As System.ComponentModel.IContainer

    'NOTE: The following procedure is required by the Windows Form Designer
    'It can be modified using the Windows Form Designer.  
    'Do not modify it using the code editor.
    Friend WithEvents Panel2 As System.Windows.Forms.Panel
    Friend WithEvents Panel1 As System.Windows.Forms.Panel
    Friend WithEvents Button1 As System.Windows.Forms.Button
    Friend WithEvents Button2 As System.Windows.Forms.Button
    Friend WithEvents tbxOutput As System.Windows.Forms.RichTextBox
    <System.Diagnostics.DebuggerStepThrough()> _
    Private Sub InitializeComponent()
        Me.Panel2 = New System.Windows.Forms.Panel
        Me.Button1 = New System.Windows.Forms.Button
        Me.Button2 = New System.Windows.Forms.Button
        Me.Panel1 = New System.Windows.Forms.Panel
        Me.tbxOutput = New System.Windows.Forms.RichTextBox
        Me.Panel2.SuspendLayout()
        Me.Panel1.SuspendLayout()
        Me.SuspendLayout()
        '
        'Panel2
        '
        Me.Panel2.Controls.Add(Me.Button1)
        Me.Panel2.Controls.Add(Me.Button2)
        Me.Panel2.Dock = System.Windows.Forms.DockStyle.Bottom
        Me.Panel2.DockPadding.All = 20
        Me.Panel2.Location = New System.Drawing.Point(0, 320)
        Me.Panel2.Name = "Panel2"
        Me.Panel2.Size = New System.Drawing.Size(616, 64)
        Me.Panel2.TabIndex = 1
        '
        'Button1
        '
        Me.Button1.Dock = System.Windows.Forms.DockStyle.Right
        Me.Button1.Font = New System.Drawing.Font( _
            "Microsoft Sans Serif", _
            9.0!, _
            System.Drawing.FontStyle.Regular, _
            System.Drawing.GraphicsUnit.Point, _
            CType(0, Byte))
        Me.Button1.Location = New System.Drawing.Point(446, 20)
        Me.Button1.Name = "Button1"
        Me.Button1.Size = New System.Drawing.Size(75, 24)
        Me.Button1.TabIndex = 2
        Me.Button1.Text = "&Run"
        '
        'Button2
        '
        Me.Button2.Dock = System.Windows.Forms.DockStyle.Right
        Me.Button2.Font = New System.Drawing.Font( _
            "Microsoft Sans Serif", _
            9.0!, _
            System.Drawing.FontStyle.Regular, _
            System.Drawing.GraphicsUnit.Point, _
            CType(0, Byte))
        Me.Button2.Location = New System.Drawing.Point(521, 20)
        Me.Button2.Name = "Button2"
        Me.Button2.Size = New System.Drawing.Size(75, 24)
        Me.Button2.TabIndex = 3
        Me.Button2.Text = "E&xit"
        '
        'Panel1
        '
        Me.Panel1.Controls.Add(Me.tbxOutput)
        Me.Panel1.Dock = System.Windows.Forms.DockStyle.Fill
        Me.Panel1.DockPadding.All = 20
        Me.Panel1.Location = New System.Drawing.Point(0, 0)
        Me.Panel1.Name = "Panel1"
        Me.Panel1.Size = New System.Drawing.Size(616, 320)
        Me.Panel1.TabIndex = 2
        '
        'tbxOutput
        '
        Me.tbxOutput.AccessibleDescription = _
            "Displays output from application."
        Me.tbxOutput.AccessibleName = "Output textbox."
        Me.tbxOutput.Dock = System.Windows.Forms.DockStyle.Fill
        Me.tbxOutput.Location = New System.Drawing.Point(20, 20)
        Me.tbxOutput.Name = "tbxOutput"
        Me.tbxOutput.Size = New System.Drawing.Size(576, 280)
        Me.tbxOutput.TabIndex = 1
        Me.tbxOutput.Text = "Click the Run button to run the application."
        '
        'Form1
        '
        Me.AutoScaleBaseSize = New System.Drawing.Size(6, 15)
        Me.ClientSize = New System.Drawing.Size(616, 384)
        Me.Controls.Add(Me.Panel1)
        Me.Controls.Add(Me.Panel2)
        Me.Name = "Form1"
        Me.Text = "FileCodeGroup"
        Me.Panel2.ResumeLayout(False)
        Me.Panel1.ResumeLayout(False)
        Me.ResumeLayout(False)

    End Sub

#End Region
End Class
'
' This sample produces the following output:
'
' The two code groups are equal.
' Added a custom membership condition:
'    <CustomMembershipCondition class="CustomMembershipCondition"
'                               version="1"
'                               domain="contoso.com"/>
' 
' Comparing the resolved code group with the initial code group:
' The two code groups are not equal.
' 
' *** System.Security.Policy.FileCodeGroup summary ***
' A FileCodeGroup named  with Union merge logic has been created with hash
' code (113152269). It contains a Zone - Intranet membership condition with
' the Same directory FileIO - NoAccess permission set. Has the following
' policy: 
' There are 1 child elements in the code group:
' Removing the Read-only group.
' 
' This sample completed successfully; press Exit to continue.

Remarks

Caution

Code Access Security (CAS) has been deprecated across all versions of .NET Framework and .NET. Recent versions of .NET do not honor CAS annotations and produce errors if CAS-related APIs are used. Developers should seek alternative means of accomplishing security tasks.

Code groups are the building blocks of code access security policy. Each policy level consists of a root code group that can have child code groups. Each child code group can have their own child code groups; this behavior extends to any number of levels, forming a tree. Each code group has a membership condition that determines if a given assembly belongs to it based on the evidence for that assembly. Only code groups whose membership conditions match a given assembly and their child code groups apply policy.

FileCodeGroup has the same child matching semantics as UnionCodeGroup. However, FileCodeGroup returns a permission set containing a dynamically-calculated FileIOPermission that grants file access to the directory from which the code is run; UnionCodeGroup only returns a static permission set. The type of file access granted is passed as a parameter to the constructor.

This code group only matches assemblies run over a file protocol, that is, assemblies that have URLs that point to a file or UNC path.

Constructors

FileCodeGroup(IMembershipCondition, FileIOPermissionAccess)

Initializes a new instance of the FileCodeGroup class.

Properties

AttributeString	Gets a string representation of the attributes of the policy statement for the code group.
Children	Gets or sets an ordered list of the child code groups of a code group. (Inherited from CodeGroup)
Description	Gets or sets the description of the code group. (Inherited from CodeGroup)
MembershipCondition	Gets or sets the code group's membership condition. (Inherited from CodeGroup)
MergeLogic	Gets the merge logic.
Name	Gets or sets the name of the code group. (Inherited from CodeGroup)
PermissionSetName	Gets the name of the named permission set for the code group.
PolicyStatement	Gets or sets the policy statement associated with the code group. (Inherited from CodeGroup)

Methods

AddChild(CodeGroup)	Adds a child code group to the current code group. (Inherited from CodeGroup)
Copy()	Makes a deep copy of the current code group.
CreateXml(SecurityElement, PolicyLevel)	When overridden in a derived class, serializes properties and internal state specific to a derived code group and adds the serialization to the specified SecurityElement. (Inherited from CodeGroup)
Equals(CodeGroup, Boolean)	Determines whether the specified code group is equivalent to the current code group, checking the child code groups as well, if specified. (Inherited from CodeGroup)
Equals(Object)	Determines whether the specified code group is equivalent to the current code group.
FromXml(SecurityElement, PolicyLevel)	Reconstructs a security object with a given state and policy level from an XML encoding. (Inherited from CodeGroup)
FromXml(SecurityElement)	Reconstructs a security object with a given state from an XML encoding. (Inherited from CodeGroup)
GetHashCode()	Gets the hash code of the current code group.
GetType()	Gets the Type of the current instance. (Inherited from Object)
MemberwiseClone()	Creates a shallow copy of the current Object. (Inherited from Object)
ParseXml(SecurityElement, PolicyLevel)	When overridden in a derived class, reconstructs properties and internal state specific to a derived code group from the specified SecurityElement. (Inherited from CodeGroup)
RemoveChild(CodeGroup)	Removes the specified child code group. (Inherited from CodeGroup)
Resolve(Evidence)	Resolves policy for the code group and its descendants for a set of evidence.
ResolveMatchingCodeGroups(Evidence)	Resolves matching code groups.
ToString()	Returns a string that represents the current object. (Inherited from Object)
ToXml()	Creates an XML encoding of the security object and its current state. (Inherited from CodeGroup)
ToXml(PolicyLevel)	Creates an XML encoding of the security object, its current state, and the policy level within which the code exists. (Inherited from CodeGroup)