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using System; using System.Collections.Generic; using System.Web; using System.CodeDom.Compiler; using System.Reflection; namespace WebApplication1 { /// <summary> /// 动态求值 /// </summary> public class FormulaCalculator { /// <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 } ); } static FormulaCalculator() { //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); } }"; } }
调用方法:string a = FormulaCalculator.Eval("(2000+100)*0.53*16.14+500").ToString();
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原文地址:http://www.cnblogs.com/superfeeling/p/4970365.html