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WebClient.UploadDataAsync Method (Uri, String, Byte[], Object)

Uploads a data buffer to a resource identified by a URI, using the specified method and identifying token.

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

Public Sub UploadDataAsync ( _
	address As Uri, _
	method As String, _
	data As Byte(), _
	userToken As Object _
Dim instance As WebClient
Dim address As Uri
Dim method As String
Dim data As Byte()
Dim userToken As Object

instance.UploadDataAsync(address, method, data, userToken)
public void UploadDataAsync (
	Uri address, 
	String method, 
	byte[] data, 
	Object userToken
public function UploadDataAsync (
	address : Uri, 
	method : String, 
	data : byte[], 
	userToken : Object
Not applicable.



The URI of the resource to receive the data.


The HTTP method used to send the file to the resource. If null, the default is POST for http and STOR for ftp.


The data buffer to send to the resource.


A user-defined object that is passed to the method invoked when the asynchronous operation completes.

Exception typeCondition


The URI formed by combining BaseAddress and address is invalid.


An error occurred while opening the stream.


There was no response from the server hosting the resource.

This method sends a data buffer to a resource. The data buffer is sent asynchronously using thread resources that are automatically allocated from the thread pool. The data is not encoded. To receive notification when the data upload completes, add an event handler to the UploadDataCompleted event.

This method does not block the calling thread while the data is being sent. To send data and block while waiting for the server's response, use one of the UploadData methods.

Asynchronous operations that have not completed can be canceled using the CancelAsync method.

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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