C#: json字符串中的特殊字符处理

#region 实现js eval功能, 如:200+200+200-200+210 * 210
        public static decimal EvalExpression(string strExpression)
        {
            Microsoft.JScript.Vsa.VsaEngine engine = Microsoft.JScript.Vsa.VsaEngine.CreateEngine();
            if (string.IsNullOrEmpty(strExpression))
                return 0 ;
            else            
            return Convert.ToDecimal(Microsoft.JScript.Eval.JScriptEvaluate(strExpression, engine));           
        }
        #endregion

#region 将一个数据表转换成一个JSON字符串，在客户端可以直接转换成二维数组。
        /// <summary>
        /// 将一个数据表转换成一个JSON字符串，在客户端可以直接转换成二维数组。
        /// </summary>
        /// <param name="source">需要转换的表。</param>
        /// <returns></returns>
        public static string DataTableToJson(DataTable source)
        {
            if (source.Rows.Count == 0)
                return "";
            StringBuilder sb = new StringBuilder("[");
            foreach (DataRow row in source.Rows)
            {
                sb.Append("[");
                for (int i = 0; i < source.Columns.Count; i++)
                {
                    sb.Append('"' + row[i].ToString().Replace("\\", "\\\\").Replace("\'", "\\\'").Replace("\t", " ").Replace("\r", " ").Replace("\n", "<br/>").Replace("\"", "'") + "\",");
                }
                sb.Remove(sb.Length - 1, 1);
                sb.Append("],");
            }
            sb.Remove(sb.Length - 1, 1);
            sb.Append("]");
            return sb.ToString();
        }
        
        
        /// <summary>
        /// 返回JSON数据到前台
        /// </summary>
        /// <param name="dt">数据表</param>
        /// <returns>JSON字符串</returns>
        public static string DataTableToJsonParam(DataTable dt)
        {
            StringBuilder JsonString = new StringBuilder();                 
            if (dt != null && dt.Rows.Count > 0)
            {
                JsonString.Append("[ ");               
                for (int i = 0; i < dt.Rows.Count; i++)
                {
                    JsonString.Append("{ ");
                    for (int j = 0; j < dt.Columns.Count; j++)
                    {
                        if (j < dt.Columns.Count - 1)
                        {
                            JsonString.Append("\"" + dt.Columns[j].ColumnName.ToString() + "\":" + "\"" + dt.Rows[i][j].ToString().Replace("\\", "\\\\").Replace("\'", "\\\'").Replace("\t", " ").Replace("\r", " ").Replace("\n", "<br/>").Replace("\"", "'") + "\",");
                        }
                        else if (j == dt.Columns.Count - 1)
                        {
                            JsonString.Append("\"" + dt.Columns[j].ColumnName.ToString() + "\":" + "\"" + dt.Rows[i][j].ToString().Replace("\\", "\\\\").Replace("\'", "\\\'").Replace("\t", " ").Replace("\r", " ").Replace("\n", "<br/>").Replace("\"", "'") + "\"");
                        }
                    }
                    /**/
                    /*end Of String*/
                    if (i == dt.Rows.Count - 1)
                    {
                        JsonString.Append("} ");
                    }
                    else
                    {
                        JsonString.Append("}, ");
                    }
                }
                JsonString.Append("]");
                return JsonString.ToString();
            }
            else
            {
                return ""; ;
            }
        }
        #endregion