WebClient.UploadValuesAsync Method (Uri, NameValueCollection)

Note: This method is new in the .NET Framework version 2.0.

Uploads the data in the specified name/value collection to the resource identified by the specified URI. This method does not block the calling thread.

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

Public Sub UploadValuesAsync ( _
	address As Uri, _
	data As NameValueCollection _
Dim instance As WebClient
Dim address As Uri
Dim data As NameValueCollection

instance.UploadValuesAsync(address, data)
public void UploadValuesAsync (
	Uri address, 
	NameValueCollection data
public function UploadValuesAsync (
	address : Uri, 
	data : NameValueCollection



The URI of the resource to receive the collection. This URI must identify a resource that can accept a request sent with the default method. See remarks.


The NameValueCollection to send to the resource.

Exception typeCondition


data is a null reference (Nothing in Visual Basic).


The URI formed by combining BaseAddress and address is invalid.


There was no response from the server hosting the resource.

This method sends a string to a resource. The string is sent asynchronously using thread resources that are automatically allocated from the thread pool. Before uploading the string, this method converts it to a Byte array using the encoding specified in the Encoding property. To receive notification when the string upload completes, you can add an event handler to the UploadStringCompleted event.

This method does not block the calling thread while the string is being sent. To send a string and block while waiting for the server's response, use one of the UploadString 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 method uses the STOR command to upload an FTP resource. For an HTTP resource, the POST method is used.


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.

.NET Framework

Supported in: 2.0

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