FirstMatchCodeGroup Class

Definition

Namespace:

System.Security.Policy

Assembly:

System.Security.Permissions.dll

Source:

FirstMatchCodeGroup.cs

Caution

This type is obsolete. See https://go.microsoft.com/fwlink/?LinkID=155570 for more information.

Allows security policy to be defined by the union of the policy statement of a code group and that of the first child code group that matches. This class cannot be inherited.

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

[System.Obsolete("This type is obsolete. See https://go.microsoft.com/fwlink/?LinkID=155570 for more information.")]
public sealed class FirstMatchCodeGroup : System.Security.Policy.CodeGroup

[<System.Obsolete("This type is obsolete. See https://go.microsoft.com/fwlink/?LinkID=155570 for more information.")>]
type FirstMatchCodeGroup = class
    inherit CodeGroup

Public NotInheritable Class FirstMatchCodeGroup
Inherits CodeGroup

Inheritance

Object

CodeGroup

FirstMatchCodeGroup

Attributes

ObsoleteAttribute

Examples

The following example shows the use of members of the FirstMatchCodeGroup 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()
   {
      // Create a new FirstMatchCodeGroup.
      FirstMatchCodeGroup^ codeGroup = constructDefaultGroup();
      
      // Create a deep copy of the FirstMatchCodeGroup.
      FirstMatchCodeGroup^ copyCodeGroup =
         dynamic_cast<FirstMatchCodeGroup^>(codeGroup->Copy());

      // Compare the original code group with the copy.
      CompareTwoCodeGroups( codeGroup, copyCodeGroup );

      addPolicy(  &codeGroup );
      addXmlMember(  &codeGroup );
      updateMembershipCondition(  &codeGroup );
      addChildCodeGroup(  &codeGroup );

      Console::Write( L"Comparing the resolved code group " );
      Console::WriteLine( L"with the initial code group." );
      FirstMatchCodeGroup^ resolvedCodeGroup =
         ResolveGroupToEvidence( codeGroup );
      if ( CompareTwoCodeGroups( codeGroup, resolvedCodeGroup ) )
      {
         PrintCodeGroup( resolvedCodeGroup );
      }
      else
      {
         PrintCodeGroup( codeGroup );
      }

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

private:
   // Create a FirstMatchCodeGroup with an exclusive policy and membership
   // condition.
   static FirstMatchCodeGroup^ constructDefaultGroup()
   {
      // Construct a new FirstMatchCodeGroup with Read, Write, Append
      // and PathDiscovery access.
      // Create read access permission to the root directory on drive C.
      FileIOPermission^ rootFilePermissions =
         gcnew FileIOPermission( PermissionState::None );
      rootFilePermissions->AllLocalFiles = FileIOPermissionAccess::Read;
      rootFilePermissions->SetPathList( FileIOPermissionAccess::Read, L"C:\\" );
      
      // Add a permission to a named permission set.
      NamedPermissionSet^ namedPermissions =
         gcnew NamedPermissionSet( L"RootPermissions" );
      namedPermissions->AddPermission( rootFilePermissions );
      
      // Create a PolicyStatement with exclusive rights to the policy.
      PolicyStatement^ policy = gcnew PolicyStatement(
         namedPermissions,PolicyStatementAttribute::Exclusive );
      
      // Create a FirstMatchCodeGroup with a membership condition that
      // matches all code, and an exclusive policy.
      FirstMatchCodeGroup^ codeGroup = gcnew FirstMatchCodeGroup(
         gcnew AllMembershipCondition,policy );

      // Set the name of the first match code group.
      codeGroup->Name = L"TempCodeGroup";

      // Set the description of the first match code group.
      codeGroup->Description = L"Temp folder permissions group";
      return codeGroup;
   }

   // Add file permission to restrict write access to all files
   // on the local machine.
   static void addPolicy( interior_ptr<FirstMatchCodeGroup^> codeGroup )
   {
      // Set the PolicyStatement property to a policy with read access to
      // the root directory on 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 );
      
      // Create a PolicyStatement with exclusive rights to the policy.
      PolicyStatement^ policy = gcnew PolicyStatement(
         namedPermissions,PolicyStatementAttribute::Exclusive );
      ( *codeGroup )->PolicyStatement = policy;
   }

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

   // Create a child code group with read-access file permissions and add it
   // to the specified code group.
   static void addChildCodeGroup( interior_ptr<FirstMatchCodeGroup^> codeGroup )
   {
      // Create a first match code group with read access.
      FileIOPermission^ rootFilePermissions = gcnew FileIOPermission(
         PermissionState::None );
      rootFilePermissions->AllLocalFiles = FileIOPermissionAccess::Read;
      rootFilePermissions->SetPathList( FileIOPermissionAccess::Read, L"C:\\" );

      PermissionSet^ permissions = gcnew PermissionSet(
         PermissionState::Unrestricted );
      permissions->AddPermission( rootFilePermissions );

      FirstMatchCodeGroup^ tempFolderCodeGroup =
         gcnew FirstMatchCodeGroup( gcnew AllMembershipCondition,
            gcnew PolicyStatement( permissions ) );
      
      // Set the name of the child code group and add it to
      // the specified code group.
      tempFolderCodeGroup->Name = L"Read-only code group";
      ( *codeGroup )->AddChild( tempFolderCodeGroup );
   }

   // Compare the two FirstMatchCodeGroups.
   static bool CompareTwoCodeGroups( FirstMatchCodeGroup^ firstCodeGroup,
      FirstMatchCodeGroup^ secondCodeGroup )
   {
      // Compare the two specified FirstMatchCodeGroups for equality.
      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 executing evidence found
   // in the specified code group.
   static String^ ResolveEvidence( CodeGroup^ codeGroup )
   {
      String^ policyString = L"None";
      
      // Resolve the policy based on the executing assembly's evidence.
      Assembly^ assembly = Members::typeid->Assembly;
      Evidence^ executingEvidence = assembly->Evidence;

      PolicyStatement^ policy = codeGroup->Resolve( executingEvidence );

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

      return policyString;
   }

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

      return dynamic_cast<FirstMatchCodeGroup^>(resolvedCodeGroup);
   }

   // If a domain attribute is not found in the specified
   // FirstMatchCodeGroup, add a child XML element identifying a custom
   // membership condition.
   static void addXmlMember( interior_ptr<FirstMatchCodeGroup^> codeGroup )
   {
      SecurityElement^ xmlElement = ( *codeGroup )->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 );
         ( *codeGroup )->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
      // FirstMatchCodeGroup type.
      if (  !codeGroup->GetType()->Equals( FirstMatchCodeGroup::typeid ) )
      {
         throw gcnew ArgumentException( L"Expected the FirstMatchCodeGroup 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"First Match" ) )
      {
         mergeLogic = L"with first-match merge logic";
      }
      
      // Retrieve the class path for the FirstMatchCodeGroup.
      String^ firstMatchGroupClass = codeGroup->ToString();

      String^ attributeString = L"";
      // Retrieve the string representation of the FirstMatchCodeGroup's
      // attributes.
      if ( codeGroup->AttributeString != nullptr )
      {
         attributeString = codeGroup->AttributeString;
      }

      // Write a summary to the console window.
      Console::WriteLine( L"\n*** {0} summary ***", firstMatchGroupClass );
      Console::Write( L"A FirstMatchCodeGroup named " );
      Console::Write( L"{0}{1}", codeGroupName, mergeLogic );
      Console::Write( L" has been created with hash code({0}).", hashCode );
      Console::Write( L"\nThis code group contains a {0}", membershipCondition );
      Console::Write( L" membership condition with the " );
      Console::WriteLine( L"{0} permission set.", permissionSetName );

      Console::Write( L"The code group contains the following policy: " );
      Console::Write( ResolveEvidence( codeGroup ) );
      Console::Write( L"\nIt also contains the following attributes: " );
      Console::WriteLine( attributeString );

      int childCount = codeGroup->Children->Count;
      if ( childCount > 0 )
      {
         Console::Write( L"There are {0}", childCount );
         Console::WriteLine( L" child elements in the code group." );
         
         // Iterate through the child code groups to display their names
         // and then remove them from the specified code group.
         for ( int i = 0; i < childCount; i++ )
         {
            // Retrieve a child code group, which has been cast as a
            // FirstMatchCodeGroup type.
            FirstMatchCodeGroup^ childCodeGroup =
               dynamic_cast<FirstMatchCodeGroup^>(codeGroup->Children->default[ i ]);

            Console::Write( L"Removing the {0}.", childCodeGroup->Name );
            // Remove the child code group.
            codeGroup->RemoveChild( childCodeGroup );
         }
         Console::WriteLine();
      }
      else
      {
         Console::WriteLine( L" No child code groups were found in this"
         L" 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.FirstMatchCodeGroup summary ***
// A FirstMatchCodeGroup named with first-match merge logic has been created
// with hash code(113151525).
// This code group contains a Zone - Intranet membership condition with the
// permission set. The code group contains the following policy:
// It also contains the following attributes:
// There are 1 child elements in the code group.
// Removing the Read-only code 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)
    {
        // Create a new FirstMatchCodeGroup.
        FirstMatchCodeGroup codeGroup = constructDefaultGroup();

        // Create a deep copy of the FirstMatchCodeGroup.
        FirstMatchCodeGroup copyCodeGroup = 
            (FirstMatchCodeGroup)codeGroup.Copy();
        // Compare the original code group with the copy.
        CompareTwoCodeGroups(codeGroup, copyCodeGroup);

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

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

    // Create a FirstMatchCodeGroup with an exclusive policy and membership
    // condition.
    private static FirstMatchCodeGroup constructDefaultGroup()
    {
        // Construct a new FirstMatchCodeGroup with Read, Write, Append
        // and PathDiscovery access.
        // Create read access permission to the root directory on drive C.
        FileIOPermission rootFilePermissions =
            new FileIOPermission(PermissionState.None);
        rootFilePermissions.AllLocalFiles = FileIOPermissionAccess.Read;
        rootFilePermissions.SetPathList(FileIOPermissionAccess.Read,"C:\\");

        // Add a permission to a named permission set.
        NamedPermissionSet namedPermissions =
            new NamedPermissionSet("RootPermissions");
        namedPermissions.AddPermission(rootFilePermissions);

        // Create a PolicyStatement with exclusive rights to the policy.
        PolicyStatement policy = new PolicyStatement(
            namedPermissions,PolicyStatementAttribute.Exclusive);

        // Create a FirstMatchCodeGroup with a membership condition that
        // matches all code, and an exclusive policy.
        FirstMatchCodeGroup codeGroup =
            new FirstMatchCodeGroup(
            new AllMembershipCondition(),
            policy);

        // Set the name of the first match code group.
        codeGroup.Name = "TempCodeGroup";

        // Set the description of the first match code group.
        codeGroup.Description = "Temp folder permissions group";

        return codeGroup;
    }

    // Add file permission to restrict write access to all files 
    // on the local machine.
    private static void addPolicy(ref FirstMatchCodeGroup codeGroup)
    {
        // Set the PolicyStatement property to a policy with read access to
        // the root directory on 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);

        // Create a PolicyStatement with exclusive rights to the policy.
        PolicyStatement policy = new PolicyStatement(
            namedPermissions,
            PolicyStatementAttribute.Exclusive);

        codeGroup.PolicyStatement = policy;
    }

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

    // Create a child code group with read-access file permissions and add it
    // to the specified code group.
    private static void addChildCodeGroup(ref FirstMatchCodeGroup codeGroup)
    {
        // Create a first match code group with read access.
        FileIOPermission rootFilePermissions = 
            new FileIOPermission(PermissionState.None);
        rootFilePermissions.AllLocalFiles = FileIOPermissionAccess.Read;
        rootFilePermissions.SetPathList(FileIOPermissionAccess.Read,"C:\\");

        PermissionSet permissions =
            new PermissionSet(PermissionState.Unrestricted);
        permissions.AddPermission(rootFilePermissions);

        FirstMatchCodeGroup tempFolderCodeGroup = new FirstMatchCodeGroup(
            new AllMembershipCondition(), 
            new PolicyStatement(permissions));

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

    // Compare the two FirstMatchCodeGroups.
    private static bool CompareTwoCodeGroups(
        FirstMatchCodeGroup firstCodeGroup, 
        FirstMatchCodeGroup secondCodeGroup)
    {
        // Compare the two specified FirstMatchCodeGroups for equality.
        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 executing evidence found 
    // in the specified code group.
    private static string ResolveEvidence(CodeGroup codeGroup)
    {
        string policyString = "None";

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

        PolicyStatement policy = codeGroup.Resolve(executingEvidence);

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

        return policyString;
    }

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

        return (FirstMatchCodeGroup)resolvedCodeGroup;
    }

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

            codeGroup.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
        // FirstMatchCodeGroup type.
        if (!codeGroup.GetType().Equals(typeof(FirstMatchCodeGroup)))
        {
            throw new ArgumentException(
                "Expected the FirstMatchCodeGroup type.");
        }
        
        string codeGroupName = codeGroup.Name;
        string membershipCondition = codeGroup.MembershipCondition.ToString();
        string permissionSetName = codeGroup.PermissionSetName;

        int hashCode = codeGroup.GetHashCode();

        string mergeLogic = "";
        if (codeGroup.MergeLogic.Equals("First Match"))
        {
            mergeLogic = "with first-match merge logic";
        }

        // Retrieve the class path for the FirstMatchCodeGroup.
        string firstMatchGroupClass = codeGroup.ToString();

        string attributeString = "";
        // Retrieve the string representation of the FirstMatchCodeGroup's
        // attributes.
        if (codeGroup.AttributeString != null)
        {
            attributeString = codeGroup.AttributeString;
        }

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

        Console.Write("The code group contains the following policy: ");
        Console.Write(ResolveEvidence(codeGroup));
        Console.Write("\nIt also contains the following attributes: ");
        Console.WriteLine(attributeString);

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

            // Iterate through the child code groups to display their names
            // and then remove them from the specified code group.
            for (int i=0; i < childCount; i++)
            {
                // Retrieve a child code group, which has been cast as a
                // FirstMatchCodeGroup type.
                FirstMatchCodeGroup childCodeGroup = 
                    (FirstMatchCodeGroup)codeGroup.Children[i];

                Console.Write("Removing the " + childCodeGroup.Name + ".");
                // Remove the child code group.
                codeGroup.RemoveChild(childCodeGroup);
            }

            Console.WriteLine();
        }
        else
        {
            Console.WriteLine(" No child code groups were found 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.FirstMatchCodeGroup summary ***
// A FirstMatchCodeGroup named with first-match merge logic has been created
// with hash code(113151525).
// This code group contains a Zone - Intranet membership condition with the 
// permission set. The code group contains the following policy: 
// It also contains the following attributes:
// There are 1 child elements in the code group.
// Removing the Read-only code 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 = ""

        ' Create a new FirstMatchCodeGroup.
        Dim codeGroup As FirstMatchCodeGroup = constructDefaultGroup()

        ' Create a deep copy of the FirstMatchCodeGroup.
        Dim copyCodeGroup As FirstMatchCodeGroup
        copyCodeGroup = CType(codeGroup.Copy(), FirstMatchCodeGroup)

        ' Compare the original code group with the copy.
        CompareTwoCodeGroups(codeGroup, copyCodeGroup)

        addPolicy(codeGroup)
        addXmlMember(codeGroup)
        updateMembershipCondition(codeGroup)
        addChildCodeGroup(codeGroup)

        Write("Comparing the resolved code group ")
        WriteLine("with the initial code group.")

        Dim resolvedCodeGroup As FirstMatchCodeGroup
        resolvedCodeGroup = ResolveGroupToEvidence(codeGroup)
        If (CompareTwoCodeGroups(codeGroup, resolvedCodeGroup)) Then
            PrintCodeGroup(resolvedCodeGroup)
        Else
            PrintCodeGroup(codeGroup)
        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
    ' Create a FirstMatchCodeGroup with an exclusive policy and membership
    ' condition.
    Private Function constructDefaultGroup() As FirstMatchCodeGroup
        ' Construct a new FirstMatchCodeGroup with Read, Write, Append 
        ' and PathDiscovery access.
        ' Create read access permission to the root directory on drive C.
        Dim rootFilePermissions As New FileIOPermission(PermissionState.None)
        rootFilePermissions.AllLocalFiles = FileIOPermissionAccess.Read
        rootFilePermissions.SetPathList(FileIOPermissionAccess.Read, "C:\\")

        ' Add a permission to a named permission set.
        Dim namedPermissions As New NamedPermissionSet("RootPermissions")
        namedPermissions.AddPermission(rootFilePermissions)

        ' Create a PolicyStatement with exclusive rights to the policy.
        Dim policy As New PolicyStatement( _
            namedPermissions, _
            PolicyStatementAttribute.Exclusive)

        ' Create a FirstMatchCodeGroup with a membership condition that 
        ' matches all code, and an exclusive policy.
        Dim codeGroup As New FirstMatchCodeGroup( _
            New AllMembershipCondition, _
            policy)

        ' Set the name of the first match code group.
        codeGroup.Name = "TempCodeGroup"

        ' Set the description of the first match code group.
        codeGroup.Description = "Temp folder permissions group"

        Return codeGroup
    End Function

    ' Add file permission to restrict write access to all files 
    ' on the local machine.
    Private Sub addPolicy(ByRef codeGroup As FirstMatchCodeGroup)
        ' Set the PolicyStatement property to a policy with read access to the
        ' root directory on drive 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)

        ' Create a PolicyStatement with exclusive rights to the policy.
        Dim policy As New PolicyStatement( _
            namedPermissions, _
            PolicyStatementAttribute.Exclusive)

        codeGroup.PolicyStatement = policy
    End Sub

    ' Set the membership condition of the code group.
    Private Sub updateMembershipCondition( _
        ByRef codeGroup As FirstMatchCodeGroup)

        ' Set the membership condition of the specified FirstMatchCodeGroup 
        ' to the Intranet zone.
        Dim zoneCondition As _
            New ZoneMembershipCondition(SecurityZone.Intranet)
        codeGroup.MembershipCondition = zoneCondition
    End Sub

    ' Create a child code group with read-access file permissions and add it
    ' to the specified code group.
    Private Sub addChildCodeGroup(ByRef codegroup As FirstMatchCodeGroup)
        ' Create a first match code group with read access.
        Dim rootFilePermissions As New FileIOPermission(PermissionState.None)
        rootFilePermissions.AllLocalFiles = FileIOPermissionAccess.Read
        rootFilePermissions.SetPathList(FileIOPermissionAccess.Read, "C:\\")

        Dim permissions As New PermissionSet(PermissionState.Unrestricted)
        permissions.AddPermission(rootFilePermissions)

        Dim tempFolderCodeGroup = New FirstMatchCodeGroup( _
            New AllMembershipCondition, _
            New PolicyStatement(permissions))

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

    ' Compare the two FirstMatchCodeGroups.
    Private Function CompareTwoCodeGroups( _
        ByVal firstCodeGroup As FirstMatchCodeGroup, _
        ByVal secondCodeGroup As FirstMatchCodeGroup) As Boolean

        ' Compare the two specified FirstMatchCodeGroups 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 executing evidence found 
    ' in the specified code group.
    Private Function ResolveEvidence(ByVal codeGroup As CodeGroup) As String
        Dim policyString As String = "None"

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

        Dim policy As PolicyStatement = codeGroup.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 evidence from the 
    ' specified code group.
    Private Function ResolveGroupToEvidence( _
        ByVal codegroup As FirstMatchCodeGroup) _
        As FirstMatchCodeGroup

        ' Resolve matching code groups to the executing assembly.
        Dim executingAssembly As [Assembly] = Me.GetType().Assembly
        Dim evidence As Evidence = executingAssembly.Evidence
        Dim resolvedCodeGroup As CodeGroup
        resolvedCodeGroup = codegroup.ResolveMatchingCodeGroups(Evidence)

        Return CType(resolvedCodeGroup, FirstMatchCodeGroup)
    End Function

    ' If a domain attribute is not found in the specified FirstMatchCodeGroup,
    ' add a child XML element identifying a custom membership condition.
    Private Sub addXmlMember(ByRef codeGroup As FirstMatchCodeGroup)
        Dim xmlElement As SecurityElement = codeGroup.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)

            codeGroup.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 console.
    Private Sub PrintCodeGroup(ByVal codeGroup As CodeGroup)
        ' Compare the type of the specified object with the
        ' FirstMatchCodeGroup type.
        If (Not codeGroup.GetType() Is GetType(FirstMatchCodeGroup)) Then
            Throw New ArgumentException( _
                "Expected the FirstMatchCodeGroup 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("First Match")) Then
            mergeLogic = "with first-match merge logic"
        End If

        ' Retrieve the class path for the FirstMatchCodeGroup.
        Dim firstMatchGroupClass As String = codeGroup.ToString()

        Dim attributeString As String = ""
        ' Retrieve the string representation of the FirstMatchCodeGroup's
        ' attributes.
        If (Not codeGroup.AttributeString Is Nothing) Then
            attributeString = codeGroup.AttributeString
        End If

        ' Write a summary to the console window.
        WriteLine(vbCrLf + "* " + firstMatchGroupClass + " summary *")
        Write("A FirstMatchCodeGroup named ")
        Write(codeGroupName + mergeLogic)
        Write(" has been created with hash code ")
        WriteLine(hashCode.ToString() + ". ")

        Write("This code group contains a " + membershipCondition)
        Write(" membership condition with the ")
        Write(permissionSetName + " permission set. ")

        Write("The code group contains the following policy: ")
        Write(ResolveEvidence(codeGroup) + ". ")
        Write("It also contains the following attributes: ")
        WriteLine(attributeString)

        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 then remove them from the specified code group.
            For i As Int16 = 0 To childCount - 1 Step 1
                ' Retrieve each child explicitly casted as a 
                ' FirstMatchCodeGroup type.
                Dim childCodeGroup As FirstMatchCodeGroup
                childCodeGroup = _
                    CType(codeGroup.Children(i), FirstMatchCodeGroup)

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

            WriteLine("")
        Else
            WriteLine("No child code groups were found in this code group.")
        End If
    End Sub

    Private Sub WriteLine(ByVal message As String)
        tbxOutput.AppendText(message + vbCrLf)

    End Sub

    Private Sub Write(ByVal message As String)
        tbxOutput.AppendText(message)

    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 = "FirstMatchCodeGroup"
        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.FirstMatchCodeGroup summary *
' A FirstMatchCodeGroup named with first-match merge logic has been created
' with hash code 113155593. This code group contains a Zone - Intranet 
' membership condition with the  permission set. The code group contains the
' following policy: None. It also contains the following attributes: 
' There are 1 child elements in the code group.
' Removing the Read-only code 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.

Like any code group, FirstMatchCodeGroup only applies when its membership condition matches evidence for an assembly. If there is a match, it tests the membership condition of each child in order, stopping when the first match occurs. The result of FirstMatchCodeGroup is the union of the policy statement of the root code group and the policy statement of the first child group of that code group that matches.

FirstMatchCodeGroup is intended for programmatic use by application domain hosts to set domain policy.

Constructors

FirstMatchCodeGroup(IMembershipCondition, PolicyStatement)

Initializes a new instance of the FirstMatchCodeGroup class.

Properties

AttributeString	Gets a string representation of the attributes of the policy statement for the code group. (Inherited from CodeGroup)
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. (Inherited from CodeGroup)
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 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. (Inherited from CodeGroup)
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. (Inherited from CodeGroup)
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)