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DnsPermission.Union Method

Creates a permission instance that is the union of the current permission instance and the specified permission instance.

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

public override IPermission Union(
	IPermission target


Type: System.Security.IPermission

The DnsPermission instance to combine with the current instance.

Return Value

Type: System.Security.IPermission
A DnsPermission instance that represents the union of the current DnsPermission instance with the specified DnsPermission instance. If target is null, this method returns a copy of the current instance. If the current instance or target is unrestricted, this method returns a DnsPermission instance that is unrestricted; otherwise, it returns a DnsPermission instance that is restricted.




target is neither a DnsPermission nor null.

The Union method returns a DnsPermission instance that allows the access defined by either the current DnsPermission instance or the specified DnsPermission instance. Any demand that passes either permission passes their union.

The following example creates a permission instance that is the union of the current permission instance and the specified permission instance.

private void MyUnion()
   // Create a DnsPermission instance that is the union of the current DnsPermission 
   // instance and the specified DnsPermission instance.     
   DnsPermission permission = (DnsPermission)dnsPermission1.Union(dnsPermission2);
   // Print the attributes and the values of the union instance of DnsPermission.
public void useDns() {
   // Create a DnsPermission instance.
   dnsPermission1 = new DnsPermission(PermissionState.Unrestricted);
   dnsPermission2 = new DnsPermission(PermissionState.None);
   // Check for permission.
   Console.WriteLine("Attributes and Values of first DnsPermission instance :");
   Console.WriteLine("Attributes and Values of second DnsPermission instance :");
   Console.WriteLine("Union of both instances : ");
   Console.WriteLine("Intersection of both instances : ");

private void PrintKeysAndValues(Hashtable myList) {
   // Get the enumerator that can iterate through the hash tabble.
   IDictionaryEnumerator myEnumerator = myList.GetEnumerator();
   while (myEnumerator.MoveNext())
      Console.WriteLine("\t{0}:\t{1}", myEnumerator.Key, myEnumerator.Value);

.NET Framework

Supported in: 4.5.2, 4.5.1, 4.5, 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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