WebClient.OpenWriteAsync Method (Uri, String, Object)
Assembly: System (in system.dll)
The URI of the resource to receive the data.
The method used to send the data to the resource. If null, the default is POST for http and STOR for ftp.
A user-defined object that is passed to the method invoked when the asynchronous operation completes
This method retrieves a writable stream that is used to send data to a resource. The stream is retrieved asynchronously using thread resources that are automatically allocated from the thread pool. To receive notification when the stream is available, add an event handler to the OpenWriteCompleted event. The contents of the stream are sent to the server when you close the stream.
If the method parameter specifies a method that is not understood by the server, the underlying protocol classes determine what occurs. Typically, a WebException is thrown with the Status property set to indicate the error.
Asynchronous operations that have not completed can be canceled using the CancelAsync method.
This method does not block the calling thread while the stream is being opened. To block while waiting for the stream, use one of the OpenWrite methods.
If the BaseAddress property is not an empty string ("") and address does not contain an absolute URI, address must be a relative URI that is combined with BaseAddress to form the absolute URI of the requested data. If the QueryString property is not an empty string, it is appended to address.
This member outputs trace information when you enable network tracing in your application. For more information, see Network Tracing.
Windows 98, Windows 2000 SP4, Windows Millennium Edition, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see System Requirements.