SocketPermission.IsSubsetOf(IPermission) Method

Definition

Namespace:

System.Net

Assembly:

System.Security.Permissions.dll

Source:

SocketPermission.cs

Determines if the current permission is a subset of the specified permission.

public:
 override bool IsSubsetOf(System::Security::IPermission ^ target);

public override bool IsSubsetOf (System.Security.IPermission target);

override this.IsSubsetOf : System.Security.IPermission -> bool

Public Overrides Function IsSubsetOf (target As IPermission) As Boolean

Parameters

target

IPermission

A SocketPermission that is to be tested for the subset relationship.

Returns

Boolean

If target is null, this method returns true if the current instance defines no permissions; otherwise, false. If target is not null, this method returns true if the current instance defines a subset of target permissions; otherwise, false.

Exceptions

ArgumentException

target is not a SocketException.

SecurityException

DnsPermission is not granted to the method caller.

Examples

The following example uses the IsSubsetOf method to determine if one SocketPermission is the subset of another.

// Creates a SocketPermission restricting access to and from all URIs.
SocketPermission^ mySocketPermission1 = gcnew SocketPermission( PermissionState::None );

// The socket to which this permission will apply will allow connections from www.contoso.com.
mySocketPermission1->AddPermission( NetworkAccess::Accept, TransportType::Tcp,  "www.contoso.com", 11000 );

// Creates a SocketPermission which will allow the target Socket to connect with www.southridgevideo.com.
SocketPermission^ mySocketPermission2 = gcnew SocketPermission( NetworkAccess::Connect,TransportType::Tcp, "www.southridgevideo.com",11002 );

// Creates a SocketPermission from the union of two SocketPermissions.
SocketPermission^ mySocketPermissionUnion =
   (SocketPermission^)( mySocketPermission1->Union( mySocketPermission2 ) );

// Checks to see if the union was successfully created by using the IsSubsetOf method.
if ( mySocketPermission1->IsSubsetOf( mySocketPermissionUnion ) &&
   mySocketPermission2->IsSubsetOf( mySocketPermissionUnion ) )
{
   Console::WriteLine(  "This union contains permissions from both mySocketPermission1 and mySocketPermission2" );
   
   // Prints the allowable accept URIs to the console.
   Console::WriteLine(  "This union accepts connections on :" );

   IEnumerator^ myEnumerator = mySocketPermissionUnion->AcceptList;
   while ( myEnumerator->MoveNext() )
   {
      Console::WriteLine( safe_cast<EndpointPermission^>( myEnumerator->Current )->ToString() );
   }
   
   // Prints the allowable connect URIs to the console.
   Console::WriteLine(  "This union permits connections to :" );

   myEnumerator = mySocketPermissionUnion->ConnectList;
   while ( myEnumerator->MoveNext() )
   {
      Console::WriteLine( safe_cast<EndpointPermission^>( myEnumerator->Current )->ToString() );
   }
}

// Creates a SocketPermission restricting access to and from all URIs.
SocketPermission mySocketPermission1 = new SocketPermission(PermissionState.None);

// The socket to which this permission will apply will allow connections from www.contoso.com.
mySocketPermission1.AddPermission(NetworkAccess.Accept, TransportType.Tcp, "www.contoso.com", 11000);

// Creates a SocketPermission which will allow the target Socket to connect with www.southridgevideo.com.
SocketPermission mySocketPermission2 =
                           new SocketPermission(NetworkAccess.Connect, TransportType.Tcp, "www.southridgevideo.com", 11002);

// Creates a SocketPermission from the union of two SocketPermissions.
SocketPermission mySocketPermissionUnion =
                           (SocketPermission)mySocketPermission1.Union(mySocketPermission2);

// Checks to see if the union was successfully created by using the IsSubsetOf method.
if (mySocketPermission1.IsSubsetOf(mySocketPermissionUnion) &&
      mySocketPermission2.IsSubsetOf(mySocketPermissionUnion)){
     Console.WriteLine("This union contains permissions from both mySocketPermission1 and mySocketPermission2");

     // Prints the allowable accept URIs to the console.
     Console.WriteLine("This union accepts connections on :");

     IEnumerator myEnumerator = mySocketPermissionUnion.AcceptList;
  while (myEnumerator.MoveNext()) {
          Console.WriteLine(((EndpointPermission)myEnumerator.Current).ToString());
       }

        // Prints the allowable connect URIs to the console.
     Console.WriteLine("This union permits connections to :");

     myEnumerator = mySocketPermissionUnion.ConnectList;
  while (myEnumerator.MoveNext()) {
          Console.WriteLine(((EndpointPermission)myEnumerator.Current).ToString());
       }
      }

' Creates a SocketPermission restricting access to and from all URIs.
Dim mySocketPermission1 As New SocketPermission(PermissionState.None)

' The socket to which this permission will apply will allow connections from www.contoso.com.
mySocketPermission1.AddPermission(NetworkAccess.Accept, TransportType.Tcp, "www.contoso.com", 11000)

' Creates a SocketPermission which will allow the target Socket to connect with www.southridgevideo.com.
Dim mySocketPermission2 As New SocketPermission(NetworkAccess.Connect, TransportType.Tcp, "www.southridgevideo.com", 11002)

' Creates a SocketPermission from the union of two SocketPermissions.
Dim mySocketPermissionUnion As SocketPermission = CType(mySocketPermission1.Union(mySocketPermission2), SocketPermission)

' Checks to see if the union was successfully created by using the IsSubsetOf method.
If mySocketPermission1.IsSubsetOf(mySocketPermissionUnion) And mySocketPermission2.IsSubsetOf(mySocketPermissionUnion) Then
   Console.WriteLine("This union contains permissions from both mySocketPermission1 and mySocketPermission2")
   
   ' Prints the allowable accept URIs to the console.
   Console.WriteLine("This union accepts connections on :")
   
   Dim myEnumerator As IEnumerator = mySocketPermissionUnion.AcceptList
   While myEnumerator.MoveNext()
      Console.WriteLine(CType(myEnumerator.Current, EndpointPermission).ToString())
   End While
   
   Console.WriteLine("This union establishes connections on : ")
   
   ' Prints the allowable connect URIs to the console.
   Console.WriteLine("This union permits connections to :")
   
   myEnumerator = mySocketPermissionUnion.ConnectList
   While myEnumerator.MoveNext()
      Console.WriteLine(CType(myEnumerator.Current, EndpointPermission).ToString())
   End While
End If

Remarks

The current permission is a subset of the specified permission if the current permission specifies a set of operations that is wholly contained by the specified permission.

For example, a permission that represents access to 192.168.1.1:80 is a subset of a permission that represents access to 192.168.1.1:Any. If this method returns true, the current permission represents no more access to the protected resource than does the specified permission.