AsnEncodedDataEnumerator::MoveNext Method ()


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Advances to the next AsnEncodedData object in an AsnEncodedDataCollection object.

Namespace:   System.Security.Cryptography
Assembly:  System (in System.dll)

virtual bool MoveNext() sealed

Return Value

Type: System::Boolean

true, if the enumerator was successfully advanced to the next element; false, if the enumerator has passed the end of the collection.

Exception Condition

The collection was modified after the enumerator was created.

After an enumerator is created, it is positioned before the first element of the collection, and the first call to the MoveNext method moves the enumerator over the first element of the collection. Subsequent calls to MoveNext advance the enumerator past subsequent elements.

After the end of the collection is passed, calls to MoveNext return false.

An enumerator is valid as long as the collection remains unchanged. If changes are made to the collection, such as adding, modifying, or deleting elements, the enumerator becomes invalid and the next call to MoveNext can throw an InvalidOperationException.

The following code example shows how to use the AsnEncodedDataEnumerator class.

#using <System.dll>
#using <System.Security.dll>

using namespace System;
using namespace System::Security::Cryptography;
using namespace System::Security::Cryptography::X509Certificates;

int main()

   //The following example demonstrates the usage of the AsnEncodedData classes.
   // Asn encoded data is read from the extensions of an X509 certificate.

      // Open the certificate store.
      X509Store^ store = gcnew X509Store( L"MY",StoreLocation::CurrentUser );
      store->Open( static_cast<OpenFlags>(OpenFlags::ReadOnly | OpenFlags::OpenExistingOnly) );
      X509Certificate2Collection^ collection = dynamic_cast<X509Certificate2Collection^>(store->Certificates);
      X509Certificate2Collection^ fcollection = dynamic_cast<X509Certificate2Collection^>(collection->Find( X509FindType::FindByTimeValid, DateTime::Now, false ));

      // Select one or more certificates to display extensions information.
      X509Certificate2Collection^ scollection = X509Certificate2UI::SelectFromCollection(fcollection, L"Certificate Select",L"Select certificates from the following list to get extension information on that certificate",X509SelectionFlag::MultiSelection);

      // Create a new AsnEncodedDataCollection object.
      AsnEncodedDataCollection^ asncoll = gcnew AsnEncodedDataCollection;
      for ( int i = 0; i < scollection->Count; i++ )

         // Display certificate information.
         Console::ForegroundColor = ConsoleColor::Red;
         Console::WriteLine( L"Certificate name: {0}", scollection[i]->GetName() );

         // Display extensions information.
         System::Collections::IEnumerator^ myEnum = scollection[i]->Extensions->GetEnumerator();
         while ( myEnum->MoveNext() )
            X509Extension^ extension = safe_cast<X509Extension ^>(myEnum->Current);

            // Create an AsnEncodedData object using the extensions information.
            AsnEncodedData^ asndata = gcnew AsnEncodedData( extension->Oid,extension->RawData );
            Console::ForegroundColor = ConsoleColor::Green;
            Console::WriteLine( L"Extension type: {0}", extension->Oid->FriendlyName );
            Console::WriteLine( L"Oid value: {0}", asndata->Oid->Value );
            Console::WriteLine( L"Raw data length: {0} {1}", asndata->RawData->Length, Environment::NewLine );
            Console::WriteLine( asndata->Format(true) );
            Console::WriteLine( Environment::NewLine );

            // Add the AsnEncodedData object to the AsnEncodedDataCollection object.
            asncoll->Add( asndata );

         Console::WriteLine( Environment::NewLine );

      Console::ForegroundColor = ConsoleColor::Red;
      Console::WriteLine( L"Number of AsnEncodedData items in the collection: {0} {1}", asncoll->Count, Environment::NewLine );

      //Create an enumerator for moving through the collection.
      AsnEncodedDataEnumerator^ asne = asncoll->GetEnumerator();

      //You must execute a MoveNext() to get to the first item in the collection.

      // Write out AsnEncodedData in the collection.
      Console::ForegroundColor = ConsoleColor::Blue;
      Console::WriteLine( L"First AsnEncodedData in the collection: {0}", asne->Current->Format(true) );
      Console::ForegroundColor = ConsoleColor::DarkBlue;
      Console::WriteLine( L"Second AsnEncodedData in the collection: {0}", asne->Current->Format(true) );

      //Return index in the collection to the beginning.
   catch ( CryptographicException^ ) 
      Console::WriteLine( L"Information could not be written out for this certificate." );

   return 1;

.NET Framework
Available since 2.0
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