HttpWebRequest.BeginGetRequestStream Method (AsyncCallback, Object)

 
System_CAPS_noteNote

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Begins an asynchronous request for a Stream object to use to write data.

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

[<HostProtectionAttribute(SecurityAction.LinkDemand, ExternalThreading = true)>]
override BeginGetRequestStream : 
        callback:AsyncCallback *
        state:Object -> IAsyncResult

Parameters

callback
Type: System.AsyncCallback

The AsyncCallback delegate.

state
Type: System.Object

The state object for this request.

Return Value

Type: System.IAsyncResult

An IAsyncResult that references the asynchronous request.

Exception Condition
ProtocolViolationException

The Method property is GET or HEAD.

-or-

KeepAlive is true, AllowWriteStreamBuffering is false, ContentLength is -1, SendChunked is false, and Method is POST or PUT.

InvalidOperationException

The stream is being used by a previous call to BeginGetRequestStream

-or-

TransferEncoding is set to a value and SendChunked is false.

-or-

The thread pool is running out of threads.

NotSupportedException

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.

WebException

Abort was previously called.

ObjectDisposedException

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 BeginGetRequestStream method starts an asynchronous request for a stream used to send data for the HttpWebRequest. The asynchronous callback method uses the EndGetRequestStream method to return the actual stream.

The BeginGetRequestStream 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 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.

System_CAPS_noteNote

Your application cannot mix synchronous and asynchronous methods for a particular request. If you call the BeginGetRequestStream method, you must use the BeginGetResponse method to retrieve the response.

System_CAPS_noteNote

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

The following code example uses the BeginGetRequestStream method to make an asynchronous request for a stream instance.

No code example is currently available or this language may not be supported.

Universal Windows Platform
Available since 8
.NET Framework
Available since 1.1
Portable Class Library
Supported in: portable .NET platforms
Silverlight
Available since 2.0
Windows Phone Silverlight
Available since 7.0
Windows Phone
Available since 8.1
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