DnsPermission.Union(IPermission) Method

Definition

Namespace:

System.Net

Assembly:

System.Security.Permissions.dll

Source:

DnsPermission.cs

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

C#

public override System.Security.IPermission Union(System.Security.IPermission target);

Parameters

target

IPermission

The DnsPermission instance to combine with the current instance.

Returns

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.

Exceptions

ArgumentException

target is neither a DnsPermission nor null.

Examples

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

C#

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.
   PrintKeysAndValues(permission.ToXml().Attributes);
}
public void useDns() {
   // Create a DnsPermission instance.
   dnsPermission1 = new DnsPermission(PermissionState.Unrestricted);
   dnsPermission2 = new DnsPermission(PermissionState.None);
   // Check for permission.
   dnsPermission1.Demand();
   dnsPermission2.Demand();
   Console.WriteLine("Attributes and Values of first DnsPermission instance :");
   PrintKeysAndValues(dnsPermission1.ToXml().Attributes);
   Console.WriteLine("Attributes and Values of second DnsPermission instance :");
   PrintKeysAndValues(dnsPermission2.ToXml().Attributes);
   Console.WriteLine("Union of both instances : ");
   MyUnion();
   Console.WriteLine("Intersection of both instances : ");
   MyIntersection();
}

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

Remarks

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.

Applies to