HttpWebRequest.BeginGetRequestStream Method (AsyncCallback, Object)
Begins an asynchronous request for a Stream object to use to write data.
Assembly: System (in System.dll)
[<HostProtectionAttribute(SecurityAction.LinkDemand, ExternalThreading = true)>] override BeginGetRequestStream : callback:AsyncCallback * state:Object -> IAsyncResult
The state object for this request.
The request cache validator indicated that the response for this request can be served from the cache; however, requests that write data must not use the cache. This exception can occur if you are using a custom cache validator that is incorrectly implemented.
Abort was previously called.
In a .NET Compact Framework application, a request stream with zero content length was not obtained and closed correctly. For more information about handling zero content length requests, see Network Programming in the .NET Compact Framework.
Themethod requires some synchronous setup tasks to complete (DNS resolution, proxy detection, and TCP socket connection, for example) before this method becomes asynchronous. As a result, this method should never be called on a user interface (UI) thread because it might take considerable time (up to several minutes depending on network settings) to complete the initial synchronous setup tasks before an exception for an error is thrown or the method succeeds.
To learn more about the thread pool, see The Managed Thread Pool.
Your application cannot mix synchronous and asynchronous methods for a particular request. If you call the BeginGetResponse method to retrieve the response.method, you must use the
This member outputs trace information when you enable network tracing in your application. For more information, see Network Tracing in the .NET Framework.
Available since 8
Available since 1.1
Portable Class Library
Supported in: portable .NET platforms
Available since 2.0
Windows Phone Silverlight
Available since 7.0
Available since 8.1