Export (0) Print
Expand All

WebRequest.EndGetResponse Method

When overridden in a descendant class, returns a WebResponse.

[Visual Basic]
Public Overridable Function EndGetResponse( _
   ByVal asyncResult As IAsyncResult _
) As WebResponse
[C#]
public virtual WebResponse EndGetResponse(
 IAsyncResult asyncResult
);
[C++]
public: virtual WebResponse* EndGetResponse(
 IAsyncResult* asyncResult
);
[JScript]
public function EndGetResponse(
   asyncResult : IAsyncResult
) : WebResponse;

Parameters

asyncResult
An IAsyncResult that references a pending request for a response.

Return Value

A WebResponse that contains a response to the Internet request.

Exceptions

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

Remarks

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

Note   The WebRequest class is an abstract (MustInherit in Visual Basic) 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.

Example

[Visual Basic, C#, C++] The following example calls the EndGetResponse to retrieve the target resource.

[Visual Basic] 

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


[C#] 

using System;
using System.Net;
using System.IO;
using System.Text;
using System.Threading;



public class RequestState
{
  // This class stores the state of the request.
  const int BUFFER_SIZE = 1024;
  public StringBuilder requestData;
  public byte[] bufferRead;
  public WebRequest request;
  public WebResponse response;
  public Stream responseStream;
  public RequestState()
  {
    bufferRead = new byte[BUFFER_SIZE];
    requestData = new StringBuilder("");
    request = null;
    responseStream = null;
  }
}
class WebRequest_BeginGetResponse
{
  public static ManualResetEvent allDone= new ManualResetEvent(false);
  const int BUFFER_SIZE = 1024;
  static void Main()
  {
    try
    {
      // Create a new webrequest to the mentioned URL.   
      WebRequest myWebRequest= WebRequest.Create("http://www.contoso.com");
      
      // Please, set the proxy to a correct value. 
      WebProxy proxy=new WebProxy("myproxy:80");

      proxy.Credentials=new NetworkCredential("srikun","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=(IAsyncResult) myWebRequest.BeginGetResponse(new AsyncCallback(RespCallback),myRequestState);
      allDone.WaitOne();
      // Release the WebResponse resource.
      myRequestState.response.Close();
      Console.Read();
    }
    catch(WebException e)
    {
      Console.WriteLine("WebException raised!");
      Console.WriteLine("\n{0}",e.Message);
      Console.WriteLine("\n{0}",e.Status);
    } 
    catch(Exception e)
    {
      Console.WriteLine("Exception raised!");
      Console.WriteLine("Source : " + e.Source);
      Console.WriteLine("Message : " + e.Message);
    }
  }
  private static void RespCallback(IAsyncResult asynchronousResult)
  {  
    try
    {
      // Set the State of request to asynchronous.
      RequestState myRequestState=(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(ReadCallBack), myRequestState);
    
    }
    catch(WebException e)
    {
      Console.WriteLine("WebException raised!");
      Console.WriteLine("\n{0}",e.Message);
      Console.WriteLine("\n{0}",e.Status);
    } 
    catch(Exception e)
    {
      Console.WriteLine("Exception raised!");
      Console.WriteLine("Source : " + e.Source);
      Console.WriteLine("Message : " + e.Message);
    }
  }
  private static  void ReadCallBack(IAsyncResult asyncResult)
  {
    try
    {
      // Result state is set to AsyncState.
      RequestState myRequestState = (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(ReadCallBack), myRequestState);
      }
      else
      {
        Console.WriteLine("\nThe HTML page Contents are:  ");
        if(myRequestState.requestData.Length>1)
        {
          string sringContent;
          sringContent = myRequestState.requestData.ToString();
          Console.WriteLine(sringContent);
        }
        Console.WriteLine("\nPress 'Enter' key to continue........");
        responseStream.Close();
        allDone.Set();
      }
    }
    catch(WebException e)
    {
      Console.WriteLine("WebException raised!");
      Console.WriteLine("\n{0}",e.Message);
      Console.WriteLine("\n{0}",e.Status);
    } 
    catch(Exception e)
    {
      Console.WriteLine("Exception raised!");
      Console.WriteLine("Source : {0}" , e.Source);
      Console.WriteLine("Message : {0}" , e.Message);
    }

  }

}

[C++] 

#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);
   }
}

[JScript] No example is available for JScript. To view a Visual Basic, C#, or C++ example, click the Language Filter button Language Filter in the upper-left corner of the page.

Requirements

Platforms: Windows 98, Windows NT 4.0, Windows Millennium Edition, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 family, .NET Compact Framework, Common Language Infrastructure (CLI) Standard

See Also

WebRequest Class | WebRequest Members | System.Net Namespace | BeginGetResponse | Making Asynchronous Requests

Show:
© 2014 Microsoft