This documentation is archived and is not being maintained.

OpenReadCompletedEventHandler Delegate

Represents the method that will handle the OpenReadCompleted event of a WebClient.

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

public delegate void OpenReadCompletedEventHandler(
	Object^ sender, 
	OpenReadCompletedEventArgs^ e


Type: System::Object
The source of the event.
Type: System.Net::OpenReadCompletedEventArgs
A OpenReadCompletedEventArgs containing event data.

When you create a OpenReadCompletedEventHandler delegate, you identify the method that will handle the event. To associate the event with your event handler, add an instance of the delegate to the event. The event handler is called whenever the event occurs, unless you remove the delegate.

The following code example demonstrates downloading a resource for reading.

void OpenResourceForReading2( String^ address )
   WebClient^ client = gcnew WebClient;
   Uri ^uri = gcnew Uri(address);

   client->OpenReadCompleted += gcnew OpenReadCompletedEventHandler( OpenReadCallback2 );
   client->OpenReadAsync( uri );

The following method is called when the download completes.

void OpenReadCallback2( Object^ /*sender*/, OpenReadCompletedEventArgs^ e )
   Stream^ reply = nullptr;
   StreamReader^ s = nullptr;
      reply = dynamic_cast<Stream^>(e->Result);
      s = gcnew StreamReader( reply );
      Console::WriteLine( s->ReadToEnd() );
      if ( s != nullptr )
      if ( reply != nullptr )


.NET Framework

Supported in: 4, 3.5, 3.0, 2.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Portable Class Library

Supported in: Portable Class Library

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

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