c#实现的去掉头或尾部的指定字符串

代码如下：

/// <summary>
        /// 替换字符串起始位置(开头)中指定的字符串
        /// </summary>
        /// <param name="s">源串</param>
        /// <param name="searchStr">查找的串</param>
        /// <param name="replaceStr">替换的目标串</param>
        /// <returns></returns>
        public static string TrimStarString(this string s, string searchStr, string replaceStr)
        {
            var result = s;
            try
            {
                if (string.IsNullOrEmpty(result))
                {
                    return result;
                }
                if (s.Length < searchStr.Length)
                {
                    return result;
                }
                if (s.IndexOf(searchStr, 0, searchStr.Length, StringComparison.Ordinal) > -1)
                {
                    result = s.Substring(searchStr.Length);
                }
                return result;
            }
            catch (Exception e)
            {
                return result;
            }
        }
        /// <summary>
        /// 替换字符串末尾位置中指定的字符串
        /// </summary>
        /// <param name="s">源串</param>
        /// <param name="searchStr">查找的串</param>
        /// <param name="replaceStr">替换的目标串</param>
        public static string TrimEndString(this string s, string searchStr, string replaceStr)
        {
            var result = s;
            try
            {
                if (string.IsNullOrEmpty(result))
                {
                    return result;
                }
                if (s.Length < searchStr.Length)
                {
                    return result;
                }
                if (s.IndexOf(searchStr, s.Length - searchStr.Length, searchStr.Length, StringComparison.Ordinal) > -1)
                {
                    result = s.Substring(0, s.Length - searchStr.Length);
                }
                return result;
            }
            catch (Exception e)
            {
                return result;
            }
        }