DnsPermission::Union Method (IPermission^)

 
System_CAPS_noteNote

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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:
virtual IPermission^ Union(
	IPermission^ target
) override

Parameters

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.

Exception Condition
ArgumentException

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 = dynamic_cast<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 = gcnew DnsPermission( PermissionState::Unrestricted );
      dnsPermission2 = gcnew 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();
   }

.NET Framework
Available since 1.1
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