SocketPermission.Intersect Method (IPermission)

 

Returns the logical intersection between two SocketPermission instances.

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

Public Overrides Function Intersect (
	target As IPermission
) As IPermission

Parameters

target
Type: System.Security.IPermission

The SocketPermission instance to intersect with the current instance.

Return Value

Type: System.Security.IPermission

The SocketPermission instance that represents the intersection of two SocketPermission instances. If the intersection is empty, the method returns null. If the target parameter is a null reference, the method returns null.

Exception Condition
ArgumentException

The target parameter is not a SocketPermission.

SecurityException

DnsPermission is not granted to the method caller.

The intersection of two permissions is a permission that helps to protect the resources and operations protected by both permissions. Specifically, it represents the minimum permission such that any demand that passes both permissions also passes their intersection. This method overrides Intersect and is implemented to support the IPermission interface.

The following example uses the Intersect method to obtain a logical intersection between two SocketPermission instances.


Dim socketPermission1 As New SocketPermission(PermissionState.Unrestricted)

'Create a 'SocketPermission' object for two ip addresses.
Dim socketPermission2 As New SocketPermission(PermissionState.None)
Dim securityElement1 As SecurityElement = socketPermission2.ToXml()
''SocketPermission' object for 'Connect' permission
Dim securityElement2 As New SecurityElement("ConnectAccess")
'Format to specify ip address are <ip-address>#<port>#<transport-type>
'First 'SocketPermission' ip-address is '192.168.144.238' for 'All' transport types and for 'All'
' ports for the ip-address.
Dim securityElement3 As New SecurityElement("URI", "192.168.144.238#-1#3")
'Second 'SocketPermission' ip-address is '192.168.144.240' for 'All' transport types and for 'All' ports for the ip-address.
Dim securityElement4 As New SecurityElement("URI", "192.168.144.240#-1#3")
securityElement2.AddChild(securityElement3)
securityElement2.AddChild(securityElement4)
securityElement1.AddChild(securityElement2)


'Obtain a 'SocketPermission' object using 'FromXml' method.
socketPermission2.FromXml(securityElement1)

Console.WriteLine(ControlChars.Cr + "Displays the result of FromXml method : " + ControlChars.Cr)
Console.WriteLine(socketPermission2.ToString())

'Create another 'SocketPermission' object with two ip addresses.
'First 'SocketPermission' ip-address is '192.168.144.238' for 'All' transport types and for 'All' ports for the ip-address.
Dim socketPermission3 As New SocketPermission(NetworkAccess.Connect, TransportType.All, "192.168.144.238", SocketPermission.AllPorts)

'Second 'SocketPermission' ip-address is '192.168.144.239' for 'All' transport types and for 'All' ports for the ip-address.
socketPermission3.AddPermission(NetworkAccess.Connect, TransportType.All, "192.168.144.239", SocketPermission.AllPorts)

Console.WriteLine("Displays the result of AddPermission method : " + ControlChars.Cr)
Console.WriteLine(socketPermission3.ToString())

'Find the intersection between two 'SocketPermission' objects.
socketPermission1 = CType(socketPermission2.Intersect(socketPermission3), SocketPermission)

Console.WriteLine("Displays the result of Intersect method :" + ControlChars.Cr + " ")
Console.WriteLine(socketPermission1.ToString())
'Demand that the calling method have the requsite socket permission.
socketPermission1.Demand()

.NET Framework
Available since 1.1
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