HttpWebRequest.Connection Eigenschaft

Definition

Namespace:

System.Net

Assembly:

System.Net.Requests.dll

Quelle:

HttpWebRequest.cs

Dient zum Abrufen oder Festlegen des Werts des Connection HTTP-Headers.

public:
 property System::String ^ Connection { System::String ^ get(); void set(System::String ^ value); };

public string? Connection { get; set; }

member this.Connection : string with get, set

Public Property Connection As String

Eigenschaftswert

String

Der Wert des Connection HTTP-Headers. Der Standardwert ist null.

Ausnahmen

ArgumentException

Der Wert von Connection wird auf Keep-Alive oder Close festgelegt.

Beispiele

Im folgenden Codebeispiel wird die Connection-Eigenschaft verwendet, um den Wert des Verbindungs-HTTP-Headers festzulegen.

int main()
{
   try
   {
      
      // Create a new HttpWebRequest object.  Make sure that
      // a default proxy is set if you are behind a firewall.
      HttpWebRequest^ myHttpWebRequest1 = dynamic_cast<HttpWebRequest^>(WebRequest::Create( "http://www.contoso.com" ));
      myHttpWebRequest1->KeepAlive = false;
      
      // Assign the response object of HttpWebRequest to a HttpWebResponse variable.
      HttpWebResponse^ myHttpWebResponse1 = dynamic_cast<HttpWebResponse^>(myHttpWebRequest1->GetResponse());
      Console::WriteLine( "\nThe HTTP request Headers for the first request are: \n {0}", myHttpWebRequest1->Headers );
      Console::WriteLine( "Press Enter Key to Continue.........." );
      Console::Read();
      Stream^ streamResponse = myHttpWebResponse1->GetResponseStream();
      StreamReader^ streamRead = gcnew StreamReader( streamResponse );
      array<Char>^readBuff = gcnew array<Char>(256);
      int count = streamRead->Read( readBuff, 0, 256 );
      Console::WriteLine( "The contents of the Html page are.......\n" );
      while ( count > 0 )
      {
         String^ outputData = gcnew String( readBuff,0,count );
         Console::Write( outputData );
         count = streamRead->Read( readBuff, 0, 256 );
      }
      Console::WriteLine();
      
      // Close the Stream object.
      streamResponse->Close();
      streamRead->Close();
      
      // Release the resources held by response object.
      myHttpWebResponse1->Close();
      
      // Create a new HttpWebRequest object for the specified Uri.
      HttpWebRequest^ myHttpWebRequest2 = dynamic_cast<HttpWebRequest^>(WebRequest::Create( "http://www.contoso.com" ));
      myHttpWebRequest2->Connection = "Close";
      
      // Assign the response object of 'HttpWebRequest' to a 'HttpWebResponse' variable.
      HttpWebResponse^ myHttpWebResponse2 = dynamic_cast<HttpWebResponse^>(myHttpWebRequest2->GetResponse());
      
      // Release the resources held by response object.
      myHttpWebResponse2->Close();
      Console::WriteLine( "\nThe Http RequestHeaders are \n {0}", myHttpWebRequest2->Headers );
      
      Console::WriteLine( "\nPress 'Enter' Key to Continue........." );
      Console::Read();
   }
   catch ( ArgumentException^ e ) 
   {
      Console::WriteLine( "\nThe second HttpWebRequest Object* has raised an Argument Exception as 'Connection' Property is set to 'Close'" );
      Console::WriteLine( "\n {0}", e->Message );
   }
   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 );
   }

}

class HttpWebRequest_Connection
{
  static void Main()
  {
    try
    {

      // Create a new HttpWebRequest object.Make sure that
      // a default proxy is set if you are behind a firewall.
      HttpWebRequest myHttpWebRequest1 =
        (HttpWebRequest)WebRequest.Create("http://www.contoso.com");

      myHttpWebRequest1.KeepAlive=false;
      // Assign the response object of HttpWebRequest to a HttpWebResponse variable.
      HttpWebResponse myHttpWebResponse1 =
        (HttpWebResponse)myHttpWebRequest1.GetResponse();

      Console.WriteLine("\nThe HTTP request Headers for the first request are: \n{0}",myHttpWebRequest1.Headers);
      Console.WriteLine("Press Enter Key to Continue..........");
      Console.Read();

      Stream streamResponse=myHttpWebResponse1.GetResponseStream();
      StreamReader streamRead = new StreamReader( streamResponse );
      Char[] readBuff = new Char[256];
      int count = streamRead.Read( readBuff, 0, 256 );
      Console.WriteLine("The contents of the Html page are.......\n");
      while (count > 0)
      {
        String outputData = new String(readBuff, 0, count);
        Console.Write(outputData);
        count = streamRead.Read(readBuff, 0, 256);
      }
      Console.WriteLine();
      // Close the Stream object.
      streamResponse.Close();
      streamRead.Close();
      // Release the resources held by response object.
      myHttpWebResponse1.Close();
      // Create a new HttpWebRequest object for the specified Uri.
      HttpWebRequest myHttpWebRequest2 =
        (HttpWebRequest)WebRequest.Create("http://www.contoso.com");
      myHttpWebRequest2.Connection="Close";
      // Assign the response object of 'HttpWebRequest' to a 'HttpWebResponse' variable.
      HttpWebResponse myHttpWebResponse2 =
        (HttpWebResponse)myHttpWebRequest2.GetResponse();
      // Release the resources held by response object.
      myHttpWebResponse2.Close();
      Console.WriteLine("\nThe Http RequestHeaders are \n{0}",myHttpWebRequest2.Headers);
      Console.WriteLine("\nPress 'Enter' Key to Continue.........");
      Console.Read();
    }
    catch(ArgumentException e)
    {
      Console.WriteLine("\nThe second HttpWebRequest object has raised an Argument Exception as 'Connection' Property is set to 'Close'");
      Console.WriteLine("\n{0}",e.Message);
    }
    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);
    }
  }
}

Class HttpWebRequest_Connection
  
  Shared Sub Main()
    Try

      ' Create a new 'HttpWebRequest' object for the specified Uri. Make sure that 
      ' a default proxy is set if you are behind a firewall.
      Dim myHttpWebRequest1 As HttpWebRequest = CType(WebRequest.Create("http://www.contoso.com"), HttpWebRequest)
      myHttpWebRequest1.KeepAlive = False
      ' Assign the response object of 'HttpWebRequest' to a 'HttpWebResponse' variable.
      Dim myHttpWebResponse1 As HttpWebResponse = CType(myHttpWebRequest1.GetResponse(), HttpWebResponse)

      Console.WriteLine(ControlChars.Cr + "The HTTP request Headers for the first request are {0}", myHttpWebRequest1.Headers)
      Console.WriteLine("Press Enter Key to Continue..........")
      Console.Read()
      Dim streamResponse As Stream = myHttpWebResponse1.GetResponseStream()
      Dim streamRead As New StreamReader(streamResponse)
      Dim readBuff(256) As [Char]
      Dim count As Integer = streamRead.Read(readBuff, 0, 256)
      Console.WriteLine("The contents of the Html page are......." + ControlChars.Cr)
      While count > 0
        Dim outputData As New [String](readBuff, 0, count)
        Console.Write(outputData)
        count = streamRead.Read(readBuff, 0, 256)
      End While
      ' Close the Stream object.
      streamResponse.Close()
      streamRead.Close()
     ' Release the resources held by response object.
      myHttpWebResponse1.Close()
      Console.WriteLine()
     ' Create a new 'HttpWebRequest' object  to the specified Uri.   
      Dim myHttpWebRequest2 As HttpWebRequest = CType(WebRequest.Create("http://www.contoso.com"), HttpWebRequest)
      myHttpWebRequest2.Connection = "Close"
      ' Assign the response object of 'HttpWebRequest' to a 'HttpWebResponse' variable.
      Dim myHttpWebResponse2 As HttpWebResponse = CType(myHttpWebRequest2.GetResponse(), HttpWebResponse)
    ' Release the resources held by response object.
    myHttpWebResponse2.Close()
      Console.WriteLine(ControlChars.Cr + "The Http RequestHeaders are " + ControlChars.Cr + "{0}", myHttpWebRequest2.Headers)
      Console.WriteLine(ControlChars.Cr + "Press 'Enter' Key to Continue.........")
      Console.Read()
    Catch e As ArgumentException
      Console.WriteLine(ControlChars.Cr + "The second HttpWebRequest object has raised an Argument Exception as 'Connection' Property is set to 'Close'")
      Console.WriteLine(ControlChars.Cr + "{0}", e.Message)
    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

Hinweise

Vorsicht

WebRequest, HttpWebRequest, ServicePointund WebClient sind veraltet, und Sie sollten sie nicht für die neue Entwicklung verwenden. Verwenden Sie stattdessen HttpClient.

Die Anforderung sendet die Connection Eigenschaft als Connection HTTP-Header an die Internetressource. Wenn der Wert der KeepAlive-Eigenschaft trueist, wird der Wert "Keep-alive" am Ende der Connection-Kopfzeile angefügt.

Um den Connection HTTP-Header zu löschen, legen Sie die eigenschaft Connection auf nullfest.

Wenn Sie die eigenschaft Connection ändern, nachdem die Anforderung gestartet wurde, wird durch Aufrufen der GetRequestStream, BeginGetRequestStream, GetResponse, GetResponseoder BeginGetResponse Methode ein InvalidOperationExceptionausgelöst.

Anmerkung

Der Wert für diese Eigenschaft wird in WebHeaderCollectiongespeichert. Wenn WebHeaderCollection festgelegt ist, geht der Eigenschaftswert verloren.