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WebRequest.EndGetResponse Method

When overridden in a descendant class, returns a WebResponse.

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

'Declaration
Public Overridable Function EndGetResponse ( _
	asyncResult As IAsyncResult _
) As WebResponse
'Usage
Dim instance As WebRequest 
Dim asyncResult As IAsyncResult 
Dim returnValue As WebResponse 

returnValue = instance.EndGetResponse(asyncResult)

Parameters

asyncResult
Type: System.IAsyncResult

An IAsyncResult that references a pending request for a response.

Return Value

Type: System.Net.WebResponse
A WebResponse that contains a response to the Internet request.

ExceptionCondition
NotImplementedException

Any attempt is made to access the method, when the method is not overridden in a descendant class.

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

NoteNote:

The WebRequest class is an abstract class. The actual behavior of WebRequest instances at run time is determined by the descendant class returned by the WebRequest.Create method. For more information about default values and exceptions, see the documentation for the descendant classes, such as HttpWebRequest and FileWebRequest.

The following example calls the EndGetResponse to retrieve the target resource.

Imports System
Imports System.Net
Imports System.IO
Imports System.Text
Imports System.Threading
Imports Microsoft.VisualBasic



Public Class RequestState
  ' This class stores the state of the request 
  Private Shared BUFFER_SIZE As Integer = 1024
  Public requestData As StringBuilder
  Public bufferRead() As Byte
  Public request As WebRequest
  Public response As WebResponse
  Public responseStream As Stream

  Public Sub New()
    bufferRead = New Byte(BUFFER_SIZE) {}
    requestData = New StringBuilder("")
    request = Nothing
    responseStream = Nothing 
  End Sub ' New 
End Class ' RequestState

Class WebRequest_BeginGetResponse
  Public Shared allDone As New ManualResetEvent(False)
  Private Shared BUFFER_SIZE As Integer = 1024

  Shared Sub Main()
    Try 


      ' Create a new webrequest to the mentioned URL. 
      Dim myWebRequest As WebRequest = WebRequest.Create("http://www.contoso.com")
      'Please, set the proxy to a correct value. 
      Dim proxy As New WebProxy("itgproxy:80")
      proxy.Credentials = New NetworkCredential("srikun", "simrin123")
      myWebRequest.Proxy = proxy
      ' Create a new instance of the RequestState. 
      Dim myRequestState As New RequestState()
      ' The 'WebRequest' object is associated to the 'RequestState' object.
      myRequestState.request = myWebRequest
      ' Start the Asynchronous call for response. 
      Dim asyncResult As IAsyncResult = CType(myWebRequest.BeginGetResponse(AddressOf RespCallback, myRequestState), IAsyncResult)
      allDone.WaitOne()
	  ' Release the WebResponse resource.
	  myRequestState.response.Close()
      Console.Read()
    Catch e As WebException
      Console.WriteLine("WebException raised!")
      Console.WriteLine(ControlChars.Cr + "{0}", e.Message)
      Console.WriteLine(ControlChars.Cr + "{0}", e.Status)
    Catch e As Exception
      Console.WriteLine("Exception raised!")
      Console.WriteLine(("Source : " + e.Source))
      Console.WriteLine(("Message : " + e.Message))
    End Try 
  End Sub ' Main

  Private Shared Sub RespCallback(asynchronousResult As IAsyncResult)
    Try 
      ' Set the State of request to asynchronous. 
      Dim myRequestState As RequestState = CType(asynchronousResult.AsyncState, RequestState)
      Dim myWebRequest1 As WebRequest = myRequestState.request
      ' End the Asynchronous response.
      myRequestState.response = myWebRequest1.EndGetResponse(asynchronousResult)
      ' Read the response into a 'Stream' object. 
      Dim responseStream As Stream = myRequestState.response.GetResponseStream()
      myRequestState.responseStream = responseStream
      ' Begin the reading of the contents of the HTML page and print it to the console. 
      Dim asynchronousResultRead As IAsyncResult = responseStream.BeginRead(myRequestState.bufferRead, 0, BUFFER_SIZE, AddressOf ReadCallBack, myRequestState)
    Catch e As WebException
      Console.WriteLine("WebException raised!")
      Console.WriteLine(ControlChars.Cr + "{0}", e.Message)
      Console.WriteLine(ControlChars.Cr + "{0}", e.Status)
    Catch e As Exception
      Console.WriteLine("Exception raised!")
      Console.WriteLine(("Source : " + e.Source))
      Console.WriteLine(("Message : " + e.Message))
    End Try 
  End Sub ' RespCallback
  Private Shared Sub ReadCallBack(asyncResult As IAsyncResult)
    Try 
      ' Result state is set to AsyncState. 
      Dim myRequestState As RequestState = CType(asyncResult.AsyncState, RequestState)
      Dim responseStream As Stream = myRequestState.responseStream
      Dim read As Integer = responseStream.EndRead(asyncResult)
      ' Read the contents of the HTML page and then print to the console. 
      If read > 0 Then
        myRequestState.requestData.Append(Encoding.ASCII.GetString(myRequestState.bufferRead, 0, read))
        Dim asynchronousResult As IAsyncResult = responseStream.BeginRead(myRequestState.bufferRead, 0, BUFFER_SIZE, AddressOf ReadCallBack, myRequestState)
      Else
        Console.WriteLine(ControlChars.Cr + "The HTML page Contents are:  ")
        If myRequestState.requestData.Length > 1 Then 
          Dim sringContent As String
          sringContent = myRequestState.requestData.ToString()
          Console.WriteLine(sringContent)
        End If
        Console.WriteLine(ControlChars.Cr + "Press 'Enter' key to continue........")
        responseStream.Close()
	       allDone.Set()
      End If 
    Catch e As WebException
      Console.WriteLine("WebException raised!")
      Console.WriteLine(ControlChars.Cr + "{0}", e.Message)
      Console.WriteLine(ControlChars.Cr + "{0}", e.Status)
    Catch e As Exception
      Console.WriteLine("Exception raised!")
      Console.WriteLine("Source :{0} ", e.Source)
      Console.WriteLine("Message :{0} ", e.Message)
    End Try 
  End Sub ' ReadCallBack 

End Class ' WebRequest_BeginGetResponse
#using <mscorlib.dll>
#using <System.dll>
using namespace System;
using namespace System::Net;
using namespace System::IO;
using namespace System::Text;
using namespace System::Threading;

public __gc class RequestState {
   // This class stores the state of the request.
   static const int BUFFER_SIZE = 1024;
public:
   StringBuilder*  requestData;
   Byte  bufferRead[];
   WebRequest*  request;
   WebResponse*  response;
   Stream*  responseStream;

   RequestState() {
      bufferRead = new Byte[BUFFER_SIZE];
      requestData = new StringBuilder(S"");
      request = 0;
      responseStream = 0;
   }
};

__gc class WebRequest_BeginGetResponse {
public:
   static ManualResetEvent* allDone = new ManualResetEvent(false);
   static const int BUFFER_SIZE = 1024;

   static void RespCallback(IAsyncResult* asynchronousResult) {
      try {
         // Set the State of request to asynchronous.
         RequestState* myRequestState=dynamic_cast<RequestState*> (asynchronousResult->AsyncState);
         WebRequest*  myWebRequest1=myRequestState->request;
         // End the Asynchronous response.
         myRequestState->response =  myWebRequest1->EndGetResponse(asynchronousResult);
         // Read the response into a 'Stream' object.
         Stream*  responseStream = myRequestState->response->GetResponseStream();
         myRequestState->responseStream=responseStream;
         // Begin the reading of the contents of the HTML page and print it to the console.
         IAsyncResult* asynchronousResultRead = responseStream->BeginRead(myRequestState->bufferRead, 0, BUFFER_SIZE, new AsyncCallback(0, ReadCallBack), myRequestState);

      } catch (WebException* e) {
         Console::WriteLine(S"WebException raised!");
         Console::WriteLine(S"\n {0}", e->Message);
         Console::WriteLine(S"\n {0}", __box(e->Status));
      } catch (Exception* e) {
         Console::WriteLine(S"Exception raised!");
         Console::WriteLine(S"Source : {0}", e->Source);
         Console::WriteLine(S"Message : {0}", e->Message);
      }
   }

   static  void ReadCallBack(IAsyncResult* asyncResult) {
      try {
         // Result state is set to AsyncState.
         RequestState* myRequestState = dynamic_cast<RequestState*>(asyncResult->AsyncState);
         Stream*  responseStream = myRequestState->responseStream;
         int read = responseStream->EndRead(asyncResult);
         // Read the contents of the HTML page and then print 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(0, ReadCallBack), myRequestState);
         } else {
            Console::WriteLine(S"\nThe HTML page Contents are:  ");
            if (myRequestState->requestData->Length>1) {
               String* sringContent;
               sringContent = myRequestState->requestData->ToString();
               Console::WriteLine(sringContent);
            }
            Console::WriteLine(S"\nPress 'Enter' key to continue........");
            responseStream->Close();
            allDone->Set();
         }
      } catch (WebException* e) {
         Console::WriteLine(S"WebException raised!");
         Console::WriteLine(S"\n {0}", e->Message);
         Console::WriteLine(S"\n {0}", __box(e->Status));
      } catch (Exception* e) {
         Console::WriteLine(S"Exception raised!");
         Console::WriteLine(S"Source : {0}" , e->Source);
         Console::WriteLine(S"Message : {0}" , e->Message);
      }
   }
};

int main() {
   try {
      // Create a new webrequest to the mentioned URL.
      WebRequest* myWebRequest= WebRequest::Create(S"http://www.contoso.com");

      // Please, set the proxy to a correct value.
      WebProxy* proxy = new WebProxy(S"myproxy:80");
      proxy->Credentials = new NetworkCredential(S"srikun", S"simrin123");
      myWebRequest->Proxy=proxy;
      // Create a new instance of the RequestState.
      RequestState* myRequestState = new RequestState();
      // The 'WebRequest' object is associated to the 'RequestState' object.
      myRequestState->request = myWebRequest;
      // Start the Asynchronous call for response.
      IAsyncResult* asyncResult =
         dynamic_cast<IAsyncResult*> (myWebRequest->BeginGetResponse(new AsyncCallback(asyncResult, WebRequest_BeginGetResponse::RespCallback), myRequestState));
      WebRequest_BeginGetResponse::allDone->WaitOne();
      // Release the WebResponse resource.
      myRequestState->response->Close();
      Console::Read();
   } catch (WebException* e) {
      Console::WriteLine(S"WebException raised!");
      Console::WriteLine(S"\n {0}", e->Message);
      Console::WriteLine(S"\n {0}", __box(e->Status));
   } catch (Exception* e) {
      Console::WriteLine(S"Exception raised!");
      Console::WriteLine(S"Source : {0}", e->Source);
      Console::WriteLine(S"Message : {0}", e->Message);
   }
}

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

.NET Framework

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

.NET Compact Framework

Supported in: 3.5, 2.0, 1.0

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