HttpListenerResponse.ContentLength64 Property


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Gets or sets the number of bytes in the body data included in the response.

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

Public Property ContentLength64 As Long

Property Value

Type: System.Int64

The value of the response's Content-Length header.

Exception Condition

The value specified for a set operation is less than zero.


The response is already being sent.


This object is closed.

The Content-Length header expresses the length, in bytes, of the response's body data. When using a format that is not send the data chunked or raw, you must set the ContentLength64 property. If you do not, the HttpListener does not send the response data.

For a complete list of response headers, see the HttpResponseHeader enumeration.

The following code example demonstrates setting the value of this property.

// This example requires the System and System.Net namespaces.
public static void SimpleListenerExample(string[] prefixes)
    if (!HttpListener.IsSupported)
        Console.WriteLine ("Windows XP SP2 or Server 2003 is required to use the HttpListener class.");
    // URI prefixes are required,
    // for example "".
    if (prefixes == null || prefixes.Length == 0)
      throw new ArgumentException("prefixes");

    // Create a listener.
    HttpListener listener = new HttpListener();
    // Add the prefixes.
    foreach (string s in prefixes)
    // Note: The GetContext method blocks while waiting for a request. 
    HttpListenerContext context = listener.GetContext();
    HttpListenerRequest request = context.Request;
    // Obtain a response object.
    HttpListenerResponse response = context.Response;
    // Construct a response.
    string responseString = "<HTML><BODY> Hello world!</BODY></HTML>";
    byte[] buffer = System.Text.Encoding.UTF8.GetBytes(responseString);
    // Get a response stream and write the response to it.
    response.ContentLength64 = buffer.Length;
    System.IO.Stream output = response.OutputStream;
    // You must close the output stream.

.NET Framework
Available since 2.0
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