HttpWebRequest.KeepAlive Property

Gets or sets a value that indicates whether to make a persistent connection to the Internet resource.

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

public bool KeepAlive { get; set; }

Property Value

Type: System.Boolean
true if the request to the Internet resource should contain a Connection HTTP header with the value Keep-alive; otherwise, false. The default is true.

Set this property to true to send a Connection HTTP header with the value Keep-alive. An application uses KeepAlive to indicate a preference for persistent connections. When the KeepAlive property is true, the application makes persistent connections to the servers that support them.

NoteNote:

When using HTTP/1.1, Keep-Alive is on by default. Setting KeepAlive to false may result in sending a Connection: Close header to the server.

The following code example sets the KeepAlive property to false to avoid establishing a persistent connection with the Internet resource.

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);
    }
  }
}
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(S"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(S"\nThe HTTP request Headers for the first request are: \n {0}",
         myHttpWebRequest1->Headers);
      Console::WriteLine(S"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(S"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 =
         dynamic_cast<HttpWebRequest*>(WebRequest::Create(S"http://www.contoso.com"));
      myHttpWebRequest2->Connection=S"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(S"\nThe Http RequestHeaders are \n {0}",
         myHttpWebRequest2->Headers);
      Console::WriteLine(S"\nPress 'Enter' Key to Continue.........");
      Console::Read();
   } catch (ArgumentException* e) {
      Console::WriteLine(S"\nThe second HttpWebRequest Object* has raised an Argument Exception as 'Connection' Property is set to 'Close'");
      Console::WriteLine(S"\n {0}", e->Message);
   } 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
Was this page helpful?
(1500 characters remaining)
Thank you for your feedback

Community Additions

ADD
Show:
© 2014 Microsoft