/// <summary>
        /// 改變關鍵字的顏色
        /// </summary>
        /// <param name="key"></param>
        /// <param name="color"></param>
        public void ChangeKeyColor(string key, Color color)
        {
            Regex regex = new Regex(key);
            //找出內容中所有的要替換的關鍵字
 

            MatchCollection collection = regex.Matches(richDetails.Text);
            //對所有的要替換顏色的關鍵字逐個替換顏色    
            foreach (Match match in collection)
            {
                //開始位置、長度、顏色缺一不可
                richDetails.SelectionStart = match.Index;
                richDetails.SelectionLength 
 
= key.Length;
                richDetails.SelectionColor = color;
            }
        }