WebClient.OpenWriteAsync Method (Uri, String)
Opens a stream for writing data to the specified resource. This method does not block the calling thread.
Assembly: System (in System.dll)
'Declaration <HostProtectionAttribute(SecurityAction.LinkDemand, ExternalThreading := True)> _ Public Sub OpenWriteAsync ( _ address As Uri, _ method As String _ )
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 in the .NET Framework.
The HostProtectionAttribute attribute applied to this type or member has the following Resources property value: ExternalThreading. The HostProtectionAttribute does not affect desktop applications (which are typically started by double-clicking an icon, typing a command, or entering a URL in a browser). For more information, see the HostProtectionAttribute class or SQL Server Programming and Host Protection Attributes.