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SocketPermission.IsSubsetOf Method

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

Namespace: System.Net
Assembly: System (in system.dll)

public override bool IsSubsetOf (
	IPermission target
)
public boolean IsSubsetOf (
	IPermission target
)
public override function IsSubsetOf (
	target : IPermission
) : boolean
Not applicable.

Parameters

target

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

Return Value

If target is a null reference (Nothing in Visual Basic), this method returns true if the current instance defines no permissions; otherwise, false. If target is not a null reference (Nothing in Visual Basic), this method returns true if the current instance defines a subset of target permissions; otherwise, false.
Exception typeCondition

ArgumentException

target is not a SocketException.

SecurityException

DnsPermission is not granted to the method caller.

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.

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 = 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.
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.
        get_AcceptList();
    while (myEnumerator.MoveNext()) {
        Console.WriteLine(((EndpointPermission)myEnumerator.
            get_Current()).ToString());
    }
    // Prints the allowable connect URIs to the console.
    Console.WriteLine("This union permits connections to :");

    myEnumerator = mySocketPermissionUnion.get_ConnectList();
    while (myEnumerator.MoveNext()) {
        Console.WriteLine(((EndpointPermission)myEnumerator.
            get_Current()).ToString());
    }
}

Windows 98, Windows Server 2000 SP4, Windows Millennium Edition, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.

.NET Framework

Supported in: 3.0, 2.0, 1.1, 1.0
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