C#中动态的运算数值

最新推荐文章于 2024-06-13 10:09:01 发布

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最新推荐文章于 2024-06-13 10:09:01 发布

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CC 4.0 BY-SA版权

文章标签： c#

原文链接：http://www.cnblogs.com/z2002m/archive/2009/01/02/1366941.html

Code
  用法  Evaluator.Eval("(1*10)+2-10")

/**//// <summary>
    /// 动态求值
    /// </summary>
    public class Evaluator
    {
        /**//// <summary>
        /// 计算结果,如果表达式出错则抛出异常
        /// </summary>
        /// <param name="statement">表达式,如"1+2+3+4"</param>
        /// <returns>结果</returns>
        public static object Eval(string statement)
        {
            return _evaluatorType.InvokeMember(
                        "Eval",
                        BindingFlags.InvokeMethod,
                        null,
                        _evaluator,
                        new object[] { statement }
                     );
        }
        /**//// <summary>
        ///
        /// </summary>
        static Evaluator()
        {
            //构造JScript的编译驱动代码
            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代码
        /// </summary>
        private static readonly string _jscriptSource =

            @"class Evaluator
              {
                  public function Eval(expr : String) : String
                  {
                     return eval(expr);
                  }
              }";
    }

转载于:https://www.cnblogs.com/z2002m/archive/2009/01/02/1366941.html