SocketPermission.Union Method (IPermission)

 
System_CAPS_noteNote

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Returns the logical union between two SocketPermission instances.

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

Public Overrides Function Union (
	target As IPermission
) As IPermission

Parameters

target
Type: System.Security.IPermission

The SocketPermission instance to combine with the current instance.

Return Value

Type: System.Security.IPermission

The SocketPermission instance that represents the union of two SocketPermission instances. If target parameter is null, it returns a copy of the current instance.

Exception Condition
ArgumentException

target is not a SocketPermission.

The result of a call to Union is a permission that represents all of the access to Socket connections represented by the current instance as well as the access represented by target. Any demand that passes either the current instance or target passes their union. This method overrides Union and is implemented to support the IPermission interface.

The following example uses the Union method to return the logical union of two existing SocketPermission instances.

' 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 

.NET Framework
Available since 1.1
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