WebRequest.BeginGetResponse(AsyncCallback, Object) WebRequest.BeginGetResponse(AsyncCallback, Object) WebRequest.BeginGetResponse(AsyncCallback, Object) WebRequest.BeginGetResponse(AsyncCallback, Object) Method

定義

派生クラスでオーバーライドされると、インターネット リソースの非同期要求を開始します。When overridden in a descendant class, begins an asynchronous request for an Internet resource.

public:
 virtual IAsyncResult ^ BeginGetResponse(AsyncCallback ^ callback, System::Object ^ state);
public virtual IAsyncResult BeginGetResponse (AsyncCallback callback, object state);
abstract member BeginGetResponse : AsyncCallback * obj -> IAsyncResult
override this.BeginGetResponse : AsyncCallback * obj -> IAsyncResult
Public Overridable Function BeginGetResponse (callback As AsyncCallback, state As Object) As IAsyncResult

パラメーター

state
Object Object Object Object

非同期要求の状態情報を格納するオブジェクト。An object containing state information for this asynchronous request.

戻り値

非同期の要求を参照する IAsyncResultAn IAsyncResult that references the asynchronous request.

例外

メソッドが派生クラスでオーバーライドされていないのに、そのメソッドへのアクセスが試行されました。Any attempt is made to access the method, when the method is not overridden in a descendant class.

次の例でBeginGetResponseは、を使用して、ターゲットリソースを非同期に要求します。The following example uses BeginGetResponse to asynchronously request the target resource. リソースが取得されると、指定されたコールバックメソッドが実行されます。When the resource has been obtained, the specified callback method will be executed.

#using <System.dll>

using namespace System;
using namespace System::Net;
using namespace System::IO;
using namespace System::Text;
using namespace System::Threading;
public ref class RequestState
{
private:

   // This class stores the state of the request.
   literal int BUFFER_SIZE = 1024;

public:
   StringBuilder^ requestData;
   array<Byte>^bufferRead;
   WebRequest^ request;
   WebResponse^ response;
   Stream^ responseStream;
   RequestState()
   {
      bufferRead = gcnew array<Byte>(BUFFER_SIZE);
      requestData = gcnew StringBuilder( "" );
      request = nullptr;
      responseStream = nullptr;
   }

};

ref class WebRequest_BeginGetResponse
{
public:
   static ManualResetEvent^ allDone = gcnew ManualResetEvent( false );
   literal 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, gcnew 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 : {0}", e->Source );
         Console::WriteLine( "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, gcnew 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 );
      }

   }

};

int 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 = gcnew WebProxy( "myproxy:80" );
      proxy->Credentials = gcnew NetworkCredential( "srikun","simrin123" );
      myWebRequest->Proxy = proxy;
      
      // Create a new instance of the RequestState.
      RequestState^ myRequestState = gcnew 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( gcnew AsyncCallback( WebRequest_BeginGetResponse::RespCallback ), myRequestState ));
      WebRequest_BeginGetResponse::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 : {0}", e->Source );
      Console::WriteLine( "Message : {0}", e->Message );
   }

}


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);
    }

  }

}

Imports System.Net
Imports System.IO
Imports System.Text
Imports System.Threading

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
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

  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
  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

End Class ' WebRequest_BeginGetResponse

注釈

メソッドBeginGetResponseは、応答の非同期要求を開始します。The BeginGetResponse method starts an asynchronous request for a response. AsyncCallbackデリゲートを実装するコールバックメソッドは、 EndGetResponseメソッドを使用しWebResponseて、インターネットリソースからを返します。The callback method that implements the AsyncCallback delegate uses the EndGetResponse method to return the WebResponse from the Internet resource.

注意

WebRequest クラスabstractはクラスです。The WebRequest class is an abstract class. 実行時のインスタンスWebRequestの実際の動作は、 WebRequest.Createメソッドによって返される派生クラスによって決まります。The actual behavior of WebRequest instances at run time is determined by the descendant class returned by the WebRequest.Create method. 既定値と例外の詳細については、「」 HttpWebRequestFileWebRequest「」など、子孫クラスのドキュメントを参照してください。For more information about default values and exceptions, see the documentation for the descendant classes, such as HttpWebRequest and FileWebRequest.

注意

WebException がスローされた場合はResponseStatus例外のプロパティとプロパティを使用して、サーバーからの応答を確認します。If a WebException is thrown, use the Response and Status properties of the exception to determine the response from the server.

適用対象

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