WebClient.OpenReadTaskAsync Method

Definition

Namespace:

System.Net

Assembly:

System.Net.WebClient.dll

Opens a readable stream containing the specified resource as an asynchronous operation using a task object. These methods do not block the calling thread.

Overloads

OpenReadTaskAsync(String)	Opens a readable stream containing the specified resource as an asynchronous operation using a task object.
OpenReadTaskAsync(Uri)	Opens a readable stream containing the specified resource as an asynchronous operation using a task object.

OpenReadTaskAsync(String)

Source:

WebClient.cs

Opens a readable stream containing the specified resource as an asynchronous operation using a task object.

public:
 System::Threading::Tasks::Task<System::IO::Stream ^> ^ OpenReadTaskAsync(System::String ^ address);

public System.Threading.Tasks.Task<System.IO.Stream> OpenReadTaskAsync (string address);

member this.OpenReadTaskAsync : string -> System.Threading.Tasks.Task<System.IO.Stream>

Public Function OpenReadTaskAsync (address As String) As Task(Of Stream)

Parameters

address

String

The URI of the resource to retrieve.

Returns

Task<Stream>

The task object representing the asynchronous operation. The Result property on the task object returns a Stream used to read data from a resource.

Exceptions

ArgumentNullException

The address parameter is null.

WebException

The URI formed by combining BaseAddress and address is invalid.

-or-

An error occurred while downloading the resource.

-or-

An error occurred while opening the stream.

Remarks

Caution

WebRequest, HttpWebRequest, ServicePoint, and WebClient are obsolete, and you shouldn't use them for new development. Use HttpClient instead.

This operation will not block. The returned Task<TResult> object will complete after the a readable stream to the data resource has been opened. This method does not block the calling thread while the stream is opening.

This method retrieves a Stream instance used to access the resource specified by the address parameter. The stream is obtained using thread resources that are automatically allocated from the thread pool.

Note

You must call Stream.Close when you are finished with the Stream to avoid running out of system resources.

In .NET Framework and .NET Core 1.0, you can cancel asynchronous operations that have not completed by calling the CancelAsync method.

If the BaseAddress property is not an empty string ("") and address does not specify an absolute URI, address must be a relative URI that is combined with BaseAddress to form the absolute URI of the requested resource. If the QueryString property is not null, it is appended to address.

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

Note

This member outputs trace information when you enable network tracing in your application. For more information, see Network Tracing in .NET Framework.

See also

• Stream

OpenReadTaskAsync(Uri)

Source:

WebClient.cs

Opens a readable stream containing the specified resource as an asynchronous operation using a task object.

public:
 System::Threading::Tasks::Task<System::IO::Stream ^> ^ OpenReadTaskAsync(Uri ^ address);

public System.Threading.Tasks.Task<System.IO.Stream> OpenReadTaskAsync (Uri address);

member this.OpenReadTaskAsync : Uri -> System.Threading.Tasks.Task<System.IO.Stream>

Public Function OpenReadTaskAsync (address As Uri) As Task(Of Stream)

Parameters

address

Uri

The URI of the resource to retrieve.

Returns

Task<Stream>

The task object representing the asynchronous operation. The Result property on the task object returns a Stream used to read data from a resource.

Exceptions

ArgumentNullException

The address parameter is null.

WebException

The URI formed by combining BaseAddress and address is invalid.

-or-

An error occurred while downloading the resource.

-or-

An error occurred while opening the stream.

Remarks

Caution

WebRequest, HttpWebRequest, ServicePoint, and WebClient are obsolete, and you shouldn't use them for new development. Use HttpClient instead.

This operation will not block. The returned Task<TResult> object will complete after the a readable stream to the data resource has been opened. This method does not block the calling thread while the stream is opening.

This method retrieves a Stream instance used to access the resource specified by the address parameter. The stream is obtained using thread resources that are automatically allocated from the thread pool.

Note

You must call Stream.Close when you are finished with the Stream to avoid running out of system resources.

In .NET Framework and .NET Core 1.0, you can cancel asynchronous operations that have not completed by calling the CancelAsync method.

If the BaseAddress property is not an empty string ("") and address does not specify an absolute URI, address must be a relative URI that is combined with BaseAddress to form the absolute URI of the requested resource. If the QueryString property is not null, it is appended to address.

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

Note

This member outputs trace information when you enable network tracing in your application. For more information, see Network Tracing in .NET Framework.

See also

• Stream