Something

class Format
    {
        private int _bold;
        private int _color;

        public int Bold
        {
            get { return _bold; }
            set 
            {
                if (_color != 0)
                {
                    _bold = value;
                    public int Color
                    {
                        get { return _color; }
                        set { _color = value; }
                    }
                }

                else
                {
                    _bold = value;
                }
            }
        }

    }
   
}