asp.net字串的數學運算式計算結果

using System;using System.Collections.Generic;using System.Web;using System.CodeDom.Compiler;using System.Reflection;namespace WebApplication1{    /// <summary>    /// 動態求值    /// </summary>    public class FormulaCalculator    {        /// <summary>        /// 計算結果,如果運算式出錯則拋出異常        /// </summary>        /// <param name="statement">運算式,如"1+2+3+4"</param>        /// <returns>結果</returns>        public static object Eval(string statement)        {            return _evaluatorType.InvokeMember(                        "Eval",                        BindingFlags.InvokeMethod,                        null,                        _evaluator,                        new object[] { statement }                     );        }        static FormulaCalculator()        {            //構造JScript的編譯驅動代碼            CodeDomProvider provider = CodeDomProvider.CreateProvider("JScript");            CompilerParameters parameters;            parameters = new CompilerParameters();            parameters.GenerateInMemory = true;            CompilerResults results;            results = provider.CompileAssemblyFromSource(parameters, _jscriptSource);            Assembly assembly = results.CompiledAssembly;            _evaluatorType = assembly.GetType("Evaluator");            _evaluator = Activator.CreateInstance(_evaluatorType);        }        private static object _evaluator = null;        private static Type _evaluatorType = null;        /// <summary>        /// JScript代碼        /// </summary>        private static readonly string _jscriptSource =            @"class Evaluator              {                  public function Eval(expr : String) : String                   {                      return eval(expr);                   }              }";    }}

調用方法：string a = FormulaCalculator.Eval("(2000+100)*0.53*16.14+500").ToString();