引用javascript引擎

在网上找到的源码，可是执行不了，请前辈们看看，
执行+-*/是可以的
C# code:

using System;
using System.Collections.Generic;
using System.Text;
using System.Reflection;
using System.CodeDom.Compiler;
namespace JSProject
{
/// <summary>
/// 动态求值
/// </summary>
public class Evaluator
{
private static object _evaluator = null;
private static Type _evaluatirType = null;
private static readonly string _jscriptSource =
@"
class Evaluator{
public function Eval(expr:String):String
{
return eval(expr);
}
}
";
/// <summary>
/// 计算结果，如果表达式出错抛出异常
/// </summary>
/// <param name="statement">表达式,如"1+2+3+4"</param>
/// <returns></returns>
public static object Eval(string statement)
{
return _evaluatirType.InvokeMember("Eval", BindingFlags.InvokeMethod, null,
_evaluator, new object[] { statement});
}
static Evaluator()
{
//构造JScript的编译驱动代码
CodeDomProvider provider = CodeDomProvider.CreateProvider("JS