C#

Keys keys = Keys.Control | Keys.A;
foreach(Keys key in POSSIBLEVALUES){ //however you're managing that
   if(keys & key) == key){ //the key contains this one!

    }
}

enum Keys
        {
            A = 1,
            B = 2,
            C = 4,
            D = 8
        }

        static void Main(string[] args)
        {
            Keys keys = Keys.A | Keys.B | Keys.D;
            if ((keys & Keys.A) == Keys.A)
            {
                Console.WriteLine("A");
            }
            if ((keys & Keys.B) == Keys.B)
            {
                Console.WriteLine("B");
            }
            if ((keys & Keys.C) == Keys.C)
            {
                Console.WriteLine("C");
            }
            if ((keys & Keys.D) == Keys.D)
            {
                Console.WriteLine("D");
            }

[Flags]
enum Keys
{
    A = 1,
    B = 2,
    C = 4,
    D = 8
}

static void Main(string[] args)
{


    Keys keys = Keys.A | Keys.B | Keys.D;
    string[] strKeys = keys.ToString().Split(',');
    foreach(string key in strKeys){
        Keys newKey = (Keys)Enum.Parse(keys.GetType(),key);
        Console.WriteLine(newKey.ToString());
    }
}

while (UDPrunning == true)
{
    if (udpSocket.Available > 0)
    {
        try
        {
            IPEndPoint msgSenderInfo = new IPEndPoint(IPAddress.Any, 0);
            Byte[] incomingData = udpSocket.Receive(ref msgSenderInfo);
            // do something with the data
        }
        catch (SocketException e)
        {
            // do something to handle the exception
        }
    }
    else
    {
        // Stop the thread from using too much processor time
        Thread.Sleep(100);
    }
}

UDPrunning = false;
udpSocketThread.Join();
udpSocket.Close();