Begins an asynchronous request for a Stream object to use to write data.
Assembly: System (in System.dll)
[<HostProtectionAttribute(SecurityAction.LinkDemand, ExternalThreading = true)>] abstract BeginGetRequestStream : callback:AsyncCallback * state:Object -> IAsyncResult [<HostProtectionAttribute(SecurityAction.LinkDemand, ExternalThreading = true)>] override BeginGetRequestStream : callback:AsyncCallback * state:Object -> IAsyncResult
- Type: System.Object
The state object for this request.
The Method property is GET or HEAD.
The stream is being used by a previous call to
The thread pool is running out of threads.
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.
The method 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 some time, typically several seconds. In some environments where the webproxy scripts are not configured properly, this can take 60 seconds or more. The default value for the downloadTime attribute on the <webProxyScipt> config file element is one minute which accounts for most of the potential time delay.
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 method, you must use the BeginGetResponse method to retrieve the response.
This member outputs trace information when you enable network tracing in your application. For more information, see Network Tracing.
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.
Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.