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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 */
public boolean get_KeepAlive ()

/** @property */
public void set_KeepAlive (boolean value)

public function get KeepAlive () : boolean

public function set KeepAlive (value : boolean)

Not applicable.

Property Value

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.


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



class HttpWebRequest_Connection
{
    public static void main(String[] args)
    {
        try {
            // Create a new HttpWebRequest object.Make sure that 
            // a default proxy is set if you are behind a fure wall.
            HttpWebRequest myHttpWebRequest1 = (HttpWebRequest)
                (WebRequest.Create("http://www.contoso.com"));
            myHttpWebRequest1.set_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.get_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.set_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.get_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.get_Message());
        }
        catch (WebException e) {
            Console.WriteLine("WebException raised!");
            Console.WriteLine("\n{0}", e.get_Message());
            Console.WriteLine("\n{0}", e.get_Status());
        }
        catch (System.Exception e) {
            Console.WriteLine("Exception raised!");
            Console.WriteLine("Source :{0} ", e.get_Source());
            Console.WriteLine("Message :{0} ", e.get_Message());
        }
    } //main
} //HttpWebRequest_Connection

import System.*;
import System.IO.*;
import System.Net.*;
import System.Text.*;

class HttpWebRequest_Connection
{
    public static void main(String[] args)
    {
        try {
            // Create a new HttpWebRequest object.Make sure that 
            // a default proxy is set if you are behind a fure wall.
            HttpWebRequest myHttpWebRequest1 = (HttpWebRequest)
                (WebRequest.Create("http://www.contoso.com"));
            myHttpWebRequest1.set_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.get_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.set_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.get_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.get_Message());
        }
        catch (WebException e) {
            Console.WriteLine("WebException raised!");
            Console.WriteLine("\n{0}", e.get_Message());
            Console.WriteLine("\n{0}", e.get_Status());
        }
        catch (System.Exception e) {
            Console.WriteLine("Exception raised!");
            Console.WriteLine("Source :{0} ", e.get_Source());
            Console.WriteLine("Message :{0} ", e.get_Message());
        }
    } //main
} //HttpWebRequest_Connection

Windows 98, Windows Server 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.

.NET Framework

Supported in: 3.0, 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 2.0, 1.0

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