HttpWebRequest.EndGetResponse Method

Ends an asynchronous request to an Internet resource.

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

public override WebResponse EndGetResponse(
	IAsyncResult asyncResult
)

Parameters

asyncResult
Type: System.IAsyncResult
The pending request for a response.

Return Value

Type: System.Net.WebResponse
A WebResponse that contains the response from the Internet resource.

ExceptionCondition
ArgumentNullException

asyncResult is null.

InvalidOperationException

This method was called previously using asyncResult.

-or-

The ContentLength property is greater than 0 but the data has not been written to the request stream.

WebException

Abort was previously called.

-or-

An error occurred while processing the request.

ArgumentException

asyncResult was not returned by the current instance from a call to BeginGetResponse.

The EndGetResponse method completes an asynchronous request for an Internet resource that was started by calling the BeginGetResponse method.

Caution noteCaution

You must call the Close method to close the stream and release the connection. Failure to do so may cause your application to run out of connections.

NoteNote

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

The following code example uses the EndGetResponse method to end an asynchronous request for an Internet resource.


  try
  {      


    // Create a HttpWebrequest object to the desired URL.
    HttpWebRequest myHttpWebRequest1= (HttpWebRequest)WebRequest.Create("http://www.contoso.com");

    // Create an instance of the RequestState and assign the previous myHttpWebRequest1
    // object to it's request field.  
    RequestState myRequestState = new RequestState();  
    myRequestState.request = myHttpWebRequest1;


    // Start the asynchronous request.
    IAsyncResult result=
      (IAsyncResult) myHttpWebRequest1.BeginGetResponse(new AsyncCallback(RespCallback),myRequestState);

    allDone.WaitOne();

    // Release the HttpWebResponse resource.
    myRequestState.response.Close();
  }
  catch(WebException e)
  {
    Console.WriteLine("\nException raised!");
    Console.WriteLine("\nMessage:{0}",e.Message);
    Console.WriteLine("\nStatus:{0}",e.Status);
    Console.WriteLine("Press any key to continue..........");
  }
  catch(Exception e)
  {
    Console.WriteLine("\nException raised!");
    Console.WriteLine("Source :{0} " , e.Source);
    Console.WriteLine("Message :{0} " , e.Message);
    Console.WriteLine("Press any key to continue..........");
    Console.Read();
  }
}
private static void RespCallback(IAsyncResult asynchronousResult)
{  
  try
  {
    // State of request is asynchronous.
    RequestState myRequestState=(RequestState) asynchronousResult.AsyncState;
    HttpWebRequest  myHttpWebRequest2=myRequestState.request;
    myRequestState.response = (HttpWebResponse) myHttpWebRequest2.EndGetResponse(asynchronousResult);

    // Read the response into a Stream object.
    Stream responseStream = myRequestState.response.GetResponseStream();
    myRequestState.streamResponse=responseStream;

    // Begin the Reading of the contents of the HTML page and print it to the console.
    IAsyncResult asynchronousInputRead = responseStream.BeginRead(myRequestState.BufferRead, 0, BUFFER_SIZE, new AsyncCallback(ReadCallBack), myRequestState);
  }
  catch(WebException e)
  {
    Console.WriteLine("\nException raised!");
    Console.WriteLine("\nMessage:{0}",e.Message);
    Console.WriteLine("\nStatus:{0}",e.Status);

  }
}
private static  void ReadCallBack(IAsyncResult asyncResult)
{
  try
  {

  RequestState myRequestState = (RequestState)asyncResult.AsyncState;
  Stream responseStream = myRequestState.streamResponse;
  int read = responseStream.EndRead( asyncResult );
  // Read the HTML page and then print it to the console.
  if (read > 0)
  {
    myRequestState.requestData.Append(Encoding.ASCII.GetString(myRequestState.BufferRead, 0, read));
    IAsyncResult asynchronousResult = responseStream.BeginRead( myRequestState.BufferRead, 0, BUFFER_SIZE, new AsyncCallback(ReadCallBack), myRequestState);
  }
  else
  {
    Console.WriteLine("\nThe contents of the Html page are : ");
    if(myRequestState.requestData.Length>1)
    {
      string stringContent;
      stringContent = myRequestState.requestData.ToString();
      Console.WriteLine(stringContent);
    }
    Console.WriteLine("Press any key to continue..........");
    Console.ReadLine();

    responseStream.Close();
    allDone.Set();

  }

  }
  catch(WebException e)
  {
    Console.WriteLine("\nException raised!");
    Console.WriteLine("\nMessage:{0}",e.Message);
    Console.WriteLine("\nStatus:{0}",e.Status);

  }

}


.NET Framework

Supported in: 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Portable Class Library

Supported in: Portable Class Library

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.
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