HttpWebRequest.Connection Eigenschaft

Definition

Ruft den Wert des Connection-HTTP-Headers ab oder legt ihn fest.Gets or sets the value of the Connection HTTP header.

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

Der Wert des Connection-HTTP-Headers.The value of the Connection HTTP header. Der Standardwert ist nullsein.The default value is null.

Ausnahmen

Der Wert von Connection wird auf „Keep-Alive“ oder „Close“ festgelegt.The value of Connection is set to Keep-alive or Close.

Beispiele

Im folgenden Codebeispiel wird die Connection-Eigenschaft verwendet, um den Wert des HTTP-Verbindungs Headers festzulegen.The following code example uses the Connection property to set the value of the Connection HTTP Header.

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

Die Anforderung sendet die Connection-Eigenschaft als Connection-HTTP-Header an die Internet Ressource.The request sends the Connection property to the Internet resource as the Connection HTTP header. Wenn der Wert der KeepAlive-Eigenschaft trueist, wird der Wert "Keep-Alive" an das Ende des Connection Headers angehängt.If the value of the KeepAlive property is true, the value "Keep-alive" is appended to the end of the Connection header.

Legen Sie die Eigenschaft Connection auf nullfest, um den Connection-HTTP-Header zu löschen.To clear the Connection HTTP header, set the Connection property to null.

Wenn Sie die Connection-Eigenschaft ändern, nachdem die Anforderung durch Aufrufen der GetRequestStream-, BeginGetRequestStream-, GetResponse-oder BeginGetResponse-Methode gestartet wurde, wird ein InvalidOperationExceptionausgelöst.Changing the Connection property after the request has been started by calling the GetRequestStream, BeginGetRequestStream, GetResponse, or BeginGetResponse method throws an InvalidOperationException.

Hinweis

Der Wert für diese Eigenschaft wird in der WebHeaderCollection gespeichert.The value for this property is stored in WebHeaderCollection. Wenn WebHeaderCollection festgelegt wird, geht der Eigenschaftswert verloren.If WebHeaderCollection is set, the property value is lost.

Gilt für: