AppendCookie Method

HttpListenerResponse.AppendCookie Method (Cookie)


Adds the specified Cookie to the collection of cookies for this response.

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

public void AppendCookie(
	Cookie cookie


Type: System.Net.Cookie

The Cookieto add to the collection to be sent with this response

Exception Condition

cookie is null.

Calling this method is equivalent to calling the Add method on the collection returned by the Cookies property.

If the specified cookie does not exist in the Cookies property's collection, cookie is added. If the cookie exists in the collection, cookie replaces it.

Legacy Code Example

The following code example demonstrates adding a cookie to a response

// This example requires the System and System.Net namespaces.

public static string NextCustomerID()
    // A real-world application would do something more robust
    // to ensure uniqueness.
    return DateTime.Now.ToString();
public static void SimpleListenerCookieExample(string[] prefixes)
    // Create a listener.
    HttpListener listener = new HttpListener();
    // Add the prefixes.
    foreach (string s in prefixes)
    listener.IgnoreWriteExceptions = true;
    // Note: The GetContext method blocks while waiting for a request. 
    HttpListenerContext context = listener.GetContext();
    HttpListenerRequest request = context.Request;
    string customerID = null;

    // Did the request come with a cookie?
    Cookie cookie = request.Cookies["ID"];
    if (cookie != null)
    if (customerID !=null)
          Console.WriteLine("Found the cookie!");
    // Get the response object.
    HttpListenerResponse response = context.Response;
    // If they didn't provide a cookie containing their ID, give them one.
    if (customerID == null)
        customerID = NextCustomerID();
        Cookie cook = new Cookie("ID", customerID );
        response.AppendCookie (cook);
    // Construct a response.
    string responseString = "<HTML><BODY> Hello " + customerID + "!</BODY></HTML>";
    byte[] buffer = System.Text.Encoding.UTF8.GetBytes(responseString);
    // Get the response stream and write the response to it.
    response.ContentLength64 = buffer.Length;
    System.IO.Stream output = response.OutputStream;
    // You must close the output stream.
    // Closing the response sends the response to the client.

.NET Framework
Available since 2.0
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