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DnsPermission::FromXml Method

Reconstructs a DnsPermission instance from an XML encoding.

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

public:
virtual void FromXml(
	SecurityElement^ securityElement
) override

Parameters

securityElement
Type: System.Security::SecurityElement

The XML encoding to use to reconstruct the DnsPermission instance.

Implements

ISecurityEncodable::FromXml(SecurityElement)

ExceptionCondition
ArgumentNullException

securityElement is nullptr.

ArgumentException

securityElement is not a DnsPermission element.

The FromXml method reconstructs a DnsPermission instance from an XML encoding defined by the SecurityElement class.

Use the ToXml method to XML-encode the DnsPermission instance, including state information.

The following example reconstructs a DnsPermission instance from an XML encoding.

public:
   void ConstructDnsPermission()
   {
      try
      {
         // Create a DnsPermission instance.
         DnsPermission^ permission = gcnew DnsPermission( PermissionState::None );
         // Create a SecurityElement instance by calling the ToXml method on the 
         // DnsPermission instance. 
         // Print its attributes, which hold the  XML encoding of the DnsPermission 
         // instance.
         Console::WriteLine( "Attributes and Values of 'DnsPermission' instance :" );
         PrintKeysAndValues( permission->ToXml()->Attributes );

         // Create a SecurityElement instance.
         SecurityElement^ securityElementObj = gcnew SecurityElement( "IPermission" );
         // Add attributes and values of the SecurityElement instance corresponding to 
         // the permission instance.
         securityElementObj->AddAttribute( "version", "1" );
         securityElementObj->AddAttribute( "Unrestricted", "true" );
         securityElementObj->AddAttribute( "class", "System.Net.DnsPermission" );

         // Reconstruct a DnsPermission instance from an XML encoding.
         DnsPermission^ permission1 = gcnew DnsPermission( PermissionState::None );
         permission1->FromXml( securityElementObj );

         // Print the attributes and values of the constructed DnsPermission Object*.
         Console::WriteLine( "After reconstruction Attributes and Values of new DnsPermission instance :" );
         PrintKeysAndValues( permission1->ToXml()->Attributes );
      }
      catch ( NullReferenceException^ e ) 
      {
         Console::WriteLine( "NullReferenceException caught!!!" );
         Console::WriteLine( "Source : {0}", e->Source );
         Console::WriteLine( "Message : {0}", e->Message );
      }
      catch ( SecurityException^ e ) 
      {
         Console::WriteLine( "SecurityException caught!!!" );
         Console::WriteLine( "Source : {0}", e->Source );
         Console::WriteLine( "Message : {0}", e->Message );
      }
      catch ( ArgumentNullException^ e ) 
      {
         Console::WriteLine( "ArgumentNullException caught!!!" );
         Console::WriteLine( "Source : {0}", e->Source );
         Console::WriteLine( "Message : {0}", e->Message );
      }
      catch ( Exception^ e ) 
      {
         Console::WriteLine( "Exception caught!!!" );
         Console::WriteLine( "Source : {0}", e->Source );
         Console::WriteLine( "Message : {0}", e->Message );
      }
   }

private:
   void PrintKeysAndValues( Hashtable^ myList )
   {
      // Get the enumerator that can iterate through the hash table.
      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

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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