C#

public class Data
{
    //Default constructor
    public Command cmdCommand; //Command type (login, logout, send message, etcetera)
    public string strMessage; //Message text
    public string strName; //Name by which the client logs into the room

    public Data()
    {
        cmdCommand = Command.Null;
        strMessage = null;
        strName = null;
    }

    //Converts the bytes into an object of type Data
    public Data(byte[] data)
    {
        //The first four bytes are for the Command
        cmdCommand = (Command)BitConverter.ToInt32(data, 0);

        //The next four store the length of the name
        int nameLen = BitConverter.ToInt32(data, 4);

        //The next four store the length of the message
        int msgLen = BitConverter.ToInt32(data, 8);

        //This check makes sure that strName has been passed in the array of bytes
        if (nameLen > 0)
            strName = Encoding.UTF8.GetString(data, 12, nameLen);
        else
            strName = null;

        //This checks for a null message field
        if (msgLen > 0)
            strMessage = Encoding.UTF8.GetString(data, 12 + nameLen, msgLen);
        else
            strMessage = null;
    }

    //Converts the Data structure into an array of bytes
    public byte[] ToByte()
    {
        List<byte> result = new List<byte>();

        //First four are for the Command
        result.AddRange(BitConverter.GetBytes((int)cmdCommand));

        //Add the length of the name
        if (strName != null)
            result.AddRange(BitConverter.GetBytes(strName.Length));
        else
            result.AddRange(BitConverter.GetBytes(0));

        //Length of the message
        if (strMessage != null)
            result.AddRange(BitConverter.GetBytes(Encoding.UTF8.GetByteCount(strMessage)));
        else
            result.AddRange(BitConverter.GetBytes(0));

        //Add the name
        if (strName != null)
            result.AddRange(Encoding.UTF8.GetBytes(strName));

        //And, lastly we add the message text to our array of bytes
        if (strMessage != null)
            result.AddRange(Encoding.UTF8.GetBytes(strMessage));

        return result.ToArray();
    }
}</byte></byte>

Index and count must refer to a location within the buffer.
Parameter name: bytes
A first chance exception of type 'System.ArgumentOutOfRangeException' occurred in mscorlib.dll