实现字符串替换

1.变量定义

        //源字符串
        private static string old = string.Empty;
        //被替换的字符串
        private static string replace = string.Empty;
        //替换成的字符串
        private static string newStr = string.Empty;

2.替换方法

        /// <summary>
        /// 字符串替换
        /// </summary>
        /// <param name="strSource">源字符串</param>
        /// <param name="strFrom">被替换的字符串</param>
        /// <param name="strTo">替换成的字符串</param>
        /// <returns></returns>
        public static string Replace(string strSource, string strFrom, string strTo)
        {
            if (strSource == null)
            {
                return null;
            }
            int i = 0;
            if ((i =strSource.IndexOf(strFrom,i)) >= 0)
            {
                char[] cSrc = strSource.ToCharArray();
                char[] cTo = strTo.ToCharArray();
                int len = strFrom.Length;
                StringBuilder buf = new StringBuilder(cSrc.Length);
                //将源字符串与替换成的字符串追加
                buf.Append(cSrc,0,i).Append(cTo);
                i += len;
                int j = i;
                //继续向后查找看是否包含被替换的字符串
                while ((i = strSource.IndexOf(strFrom, i)) > 0)
                {
                    buf.Append(cSrc, j, i - j).Append(cTo);
                    i += len;
                    j = i;
                }
                buf.Append(cSrc,j,cSrc.Length-j);
                return buf.ToString();
            }
            return "字符串中没有此药替换的字符串,请重新输入";
        }