OpenWriteAsync Method (Uri, String)

WebClient.OpenWriteAsync Method (Uri, String)

Opens a stream for writing data to the specified resource. This method does not block the calling thread.

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

public void OpenWriteAsync (
	Uri address,
	string method
public void OpenWriteAsync (
	Uri address, 
	String method
public function OpenWriteAsync (
	address : Uri, 
	method : String
Not applicable.



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.

This method retrieves a writable stream that is used to send data to a resource. The stream is retrieved 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. When you close the stream, the thread blocks until the request is sent to address and a response is received.

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 Server 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 Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.

.NET Framework

Supported in: 3.0, 2.0

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