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WebClient.DownloadDataAsync Method (Uri, Object)

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

Downloads the specified resource as a Byte array. This method does not block the calling thread.

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

public void DownloadDataAsync (
	Uri address,
	Object userToken
)
public void DownloadDataAsync (
	Uri address, 
	Object userToken
)
public function DownloadDataAsync (
	address : Uri, 
	userToken : Object
)

Parameters

address

A Uri containing the URI to download.

userToken

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

Exception typeCondition

WebException

The URI formed by combining BaseAddress and address is invalid.

-or-

An error occurred while downloading the resource.

This method retrieves the specified resource using the default method for the protocol associated with the URI scheme specified in address. The data is downloaded asynchronously using thread resources that are automatically allocated from the thread pool.

This method does not block the calling thread while downloading the resource. To download a resource and block while waiting for the server's response, use one of the DownloadData methods. When the download completes, the DownloadDataCompleted event is raised. Your application must handle this event to receive notification. The downloaded data is available in the Result property.

You can use the CancelAsync method to cancel asynchronous operations that have not completed.

This method uses the RETR command to download an FTP resource. For an HTTP resource, the GET method is used.

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.

NoteNote

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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