关于公式解析的C#代码 比用反射更快 公式中去掉 Math

字符串中 Math 要大写,其余都要小写, 具体是JScript 的语法 ,   遵循就是   
//****************公式中去掉 Math
        /// <summary>
        /// 计算字符串表达式的通用类。
        /// 引用Microsoft.JScript.Eval和Microsoft.JScript.Vsa.VsaEngine来实现公式计算方法
        /// </summary>
        /// <param name="strequation">字符串表达式</param>
        /// <param name="paras">传入的参数</param>
        /// <param name="paravalues">传入参数对应的值</param>
        /// <param name="repara">返回的参数名</param>
        /// <returns></returns>
        public object RunFormula(string strequation, List<string> paras, List<string> paravalues, string repara)
        {

            StringBuilder myCode = new StringBuilder();
            myCode.Append("function getValue() : double {");
            for (int i = 0; i < paras.Count; i++)
            {
                myCode.Append("var " + paras[i] + " = " + paravalues[i] + " ;");
            }
            myCode.Append("var " + repara + "=0;  with (Math){ ");
            myCode.Append(repara + "=" + strequation + "};");
            myCode.Append("  return " + repara + ";");
            myCode.Append("}");

            try
            {
                object ret = Microsoft.JScript.Eval.JScriptEvaluate(myCode + "getValue()",
                    Microsoft.JScript.Vsa.VsaEngine.CreateEngine());
                return ret;
            }
            catch
            {
                return "false";
            }
           
        }