' Displays the header information that accompanied a request.
Public Shared Sub DisplayWebHeaderCollection(ByVal request As HttpListenerRequest)
    Dim headers As System.Collections.Specialized.NameValueCollection = request.Headers
    ' Get each header and display each value.
    For Each key As String In headers.AllKeys
        Dim values() As String = headers.GetValues(key)
        If values.Length > 0 Then
            Console.WriteLine("The values of the {0} header are: ", key)
            For Each value As String In values
                Console.WriteLine("   {0}", value)
            Next value
        Else
            Console.WriteLine("There is no value associated with the header.")
        End If
    Next key
End Sub

    // Displays the header information that accompanied a request.
public static void DisplayWebHeaderCollection(HttpListenerRequest request)
{
    System.Collections.Specialized.NameValueCollection headers = request.Headers;
    // Get each header and display each value.
    foreach (string key in headers.AllKeys)
    {
        string[] values = headers.GetValues(key);
        if(values.Length > 0) 
        {
            Console.WriteLine("The values of the {0} header are: ", key);
            foreach (string value in values) 
            {
                Console.WriteLine("   {0}", value);
            }
        }
        else
            Console.WriteLine("There is no value associated with the header.");
    }
}