C# 将字符串或表达式直接转为可执行代码的办法
反射类
using System; using System.Data; using System.Configuration; using System.Text; using System.CodeDom.Compiler; using Microsoft.CSharp; using System.Reflection; namespace SSEC.Math { /// <summary> /// 本类用来将字符串转为可执行文本并执行 /// </summary> public class MyEvaluator { #region 构造函数 /// <summary> /// 可执行串的构造函数 /// </summary> /// <param name="items"> /// 可执行字符串数组 /// </param> public MyEvaluator(EvaluatorItem[] items) { ConstructEvaluator(items); //调用解析字符串构造函数进行解析 } /// <summary> /// 可执行串的构造函数 /// </summary> /// <param name="returnType">返回值类型</param> /// <param name="expression">执行表达式</param> /// <param name="name">执行字符串名称</param> public MyEvaluator(Type returnType, string expression, string name) { //创建可执行字符串数组 EvaluatorItem[] items = { new EvaluatorItem(returnType, expression, name) }; ConstructEvaluator(items); //调用解析字符串构造函数进行解析 } /// <summary> /// 可执行串的构造函数 /// </summary> /// <param name="item">可执行字符串项</param> public MyEvaluator(EvaluatorItem item) { EvaluatorItem[] items = { item };//将可执行字符串项转为可执行字符串项数组 ConstructEvaluator(items); //调用解析字符串构造函数进行解析 } /// <summary> /// 解析字符串构造函数 /// </summary> /// <param name="items">待解析字符串数组</param> private void ConstructEvaluator(EvaluatorItem[] items) { //创建C#编译器实例 CodeDomProvider provider = CodeDomProvider.CreateProvider("C#"); //过时了 //ICodeCompiler comp = provider.CreateCompiler(); //编译器的传入参数 CompilerParameters cp = new CompilerParameters(); cp.ReferencedAssemblies.Add("system.dll"); //添加程序集 system.dll 的引用 cp.ReferencedAssemblies.Add("system.data.dll"); //添加程序集 system.data.dll 的引用 cp.ReferencedAssemblies.Add("system.xml.dll"); //添加程序集 system.xml.dll 的引用 cp.GenerateExecutable = false; //不生成可执行文件 cp.GenerateInMemory = true; //在内存中运行 StringBuilder code = new StringBuilder(); //创建代码串 /* * 添加常见且必须的引用字符串 */ code.Append("using System; /n"); code.Append("using System.Data; /n"); code.Append("using System.Data.SqlClient; /n"); code.Append("using System.Data.OleDb; /n"); code.Append("using System.Xml; /n"); code.Append("namespace SSEC.Math { /n"); //生成代码的命名空间为EvalGuy,和本代码一样 code.Append(" public class _Evaluator { /n"); //产生 _Evaluator 类,所有可执行代码均在此类中运行 foreach (EvaluatorItem item in items) //遍历每一个可执行字符串项 { code.AppendFormat(" public {0} {1}() ", //添加定义公共函数代码 item.ReturnType.Name, //函数返回值为可执行字符串项中定义的返回值类型 item.Name); //函数名称为可执行字符串项中定义的执行字符串名称 code.Append("{ "); //添加函数开始括号 code.AppendFormat("return ({0});", item.Expression);//添加函数体,返回可执行字符串项中定义的表达式的值 code.Append("}/n"); //添加函数结束括号 } code.Append("} }"); //添加类结束和命名空间结束括号 //得到编译器实例的返回结果 CompilerResults cr = provider.CompileAssemblyFromSource(cp, code.ToString());//comp if (cr.Errors.HasErrors) //如果有错误 { StringBuilder error = new StringBuilder(); //创建错误信息字符串 error.Append("编译有错误的表达式: "); //添加错误文本 foreach (CompilerError err in cr.Errors) //遍历每一个出现的编译错误 { error.AppendFormat("{0}/n", err.ErrorText); //添加进错误文本,每个错误后换行 } throw new Exception("编译错误: " + error.ToString());//抛出异常 } Assembly a = cr.CompiledAssembly; //获取编译器实例的程序集 _Compiled = a.CreateInstance("SSEC.Math._Evaluator"); //通过程序集查找并声明 SSEC.Math._Evaluator 的实例 } #endregion #region 公有成员 /// <summary> /// 执行字符串并返回整型值 /// </summary> /// <param name="name">执行字符串名称</param> /// <returns>执行结果</returns> public int EvaluateInt(string name) { return (int)Evaluate(name); } /// <summary> /// 执行字符串并返回双精度值 /// </summary> /// <param name="name">执行字符串名称</param> /// <returns>执行结果</returns> public double EvaluateDouble(string name) { return (double)Evaluate(name); } /// <summary> /// 执行字符串并返回长整型数值 /// </summary> /// <param name="name">执行字符串名称</param> /// <returns>执行结果</returns> public long EvaluateLong(string name) { return (long)Evaluate(name); } /// <summary> /// 执行字符串并返回十进制数值 /// </summary> /// <param name="name">执行字符串名称</param> /// <returns>执行结果</returns> public decimal EvaluateDecimal(string name) { return (decimal)Evaluate(name); } /// <summary> /// 执行字符串并返回字符串型值 /// </summary> /// <param name="name">执行字符串名称</param> /// <returns>执行结果</returns> public string EvaluateString(string name) { return (string)Evaluate(name); } /// <summary> /// 执行字符串并返回布尔型值 /// </summary> /// <param name="name">执行字符串名称</param> /// <returns>执行结果</returns> public bool EvaluateBool(string name) { return (bool)Evaluate(name); } /// <summary> /// 执行字符串并返 object 型值 /// </summary> /// <param name="name">执行字符串名称</param> /// <returns>执行结果</returns> public object Evaluate(string name) { MethodInfo mi = _Compiled.GetType().GetMethod(name);//获取 _Compiled 所属类型中名称为 name 的方法的引用 return mi.Invoke(_Compiled, null); //执行 mi 所引用的方法 } #endregion #region 静态成员 /// <summary> /// 执行表达式并返回整型值 /// </summary> /// <param name="code">要执行的表达式</param> /// <returns>运算结果</returns> static public int EvaluateToInteger(string code) { MyEvaluator eval = new MyEvaluator(typeof(int), code, staticMethodName);//生成 Evaluator 类的对像 return (int)eval.Evaluate(staticMethodName); //执行并返回整型数据 } /// <summary> /// 执行表达式并返回双精度值 /// </summary> /// <param name="name">执行字符串名称</param> /// <returns>执行结果</returns> static public double EvaluateToDouble(string code) { MyEvaluator eval = new MyEvaluator(typeof(double), code, staticMethodName);//生成 Evaluator 类的对像 return (double)eval.Evaluate(staticMethodName); } /// <summary> /// 执行表达式并返回长整型数值 /// </summary> /// <param name="name">执行字符串名称</param> /// <returns>执行结果</returns> static public long EvaluateToLong(string code) { MyEvaluator eval = new MyEvaluator(typeof(long), code, staticMethodName);//生成 Evaluator 类的对像 return (long)eval.Evaluate(staticMethodName); } /// <summary> /// 执行表达式并返回十进制数值 /// </summary> /// <param name="name">执行字符串名称</param> /// <returns>执行结果</returns> static public decimal EvaluateToDecimal(string code) { MyEvaluator eval = new MyEvaluator(typeof(decimal), code, staticMethodName);//生成 Evaluator 类的对像 return (decimal)eval.Evaluate(staticMethodName); } /// <summary> /// 执行表达式并返回字符串型值 /// </summary> /// <param name="code">要执行的表达式</param> /// <returns>运算结果</returns> static public string EvaluateToString(string code) { MyEvaluator eval = new MyEvaluator(typeof(string), code, staticMethodName);//生成 Evaluator 类的对像 return (string)eval.Evaluate(staticMethodName); //执行并返回字符串型数据 } /// <summary> /// 执行表达式并返回布尔型值 /// </summary> /// <param name="code">要执行的表达式</param> /// <returns>运算结果</returns> static public bool EvaluateToBool(string code) { MyEvaluator eval = new MyEvaluator(typeof(bool), code, staticMethodName);//生成 Evaluator 类的对像 return (bool)eval.Evaluate(staticMethodName); //执行并返回布尔型数据 } /// <summary> /// 执行表达式并返回 object 型值 /// </summary> /// <param name="code">要执行的表达式</param> /// <returns>运算结果</returns> static public object EvaluateToObject(string code) { MyEvaluator eval = new MyEvaluator(typeof(object), code, staticMethodName);//生成 Evaluator 类的对像 return eval.Evaluate(staticMethodName); //执行并返回 object 型数据 } #endregion #region 私有成员 /// <summary> /// 静态方法的执行字符串名称 /// </summary> private const string staticMethodName = "__foo"; /// <summary> /// 用于动态引用生成的类,执行其内部包含的可执行字符串 /// </summary> object _Compiled = null; #endregion } /// <summary> /// 可执行字符串项(即一条可执行字符串) /// </summary> public class EvaluatorItem { /// <summary> /// 返回值类型 /// </summary> public Type ReturnType; /// <summary> /// 执行表达式 /// </summary> public string Expression; /// <summary> /// 执行字符串名称 /// </summary> public string Name; /// <summary> /// 可执行字符串项构造函数 /// </summary> /// <param name="returnType">返回值类型</param> /// <param name="expression">执行表达式</param> /// <param name="name">执行字符串名称</param> public EvaluatorItem(Type returnType, string expression, string name) { ReturnType = returnType; Expression = expression; Name = name; } } }
测试类:
class Test { /// <summary> /// The main entry point for the application. /// </summary> [STAThread] static void Main(string[] args) { Console.WriteLine("Test0: {0}", MyEvaluator.EvaluateToInteger("(30 + 4) * 2")); Console.WriteLine("Test1: {0}", MyEvaluator.EvaluateToString("/"Hello /" + /"There/"")); Console.WriteLine("Test2: {0}", MyEvaluator.EvaluateToBool("30 == 40")); Console.WriteLine("Test3: {0}", MyEvaluator.EvaluateToObject("new DataSet()")); Console.WriteLine("Test4: {0}", MyEvaluator.EvaluateToDouble("(12.4+2.2)*0.4")); Console.WriteLine("Test5: {0}", MyEvaluator.EvaluateToLong("(12+1000)*1000")); Console.WriteLine("Test6: {0}", MyEvaluator.EvaluateToString("/"double max==/"+double.MaxValue"));//decimal.MaxValue+/",/"+ EvaluatorItem[] items = { new EvaluatorItem(typeof(int), "(30 + 4) * 2", "GetNumber"), new EvaluatorItem(typeof(string), "/"Hello /" + /"There/"", "GetString"), new EvaluatorItem(typeof(bool), "30 == 40", "GetBool"), new EvaluatorItem(typeof(object), "new DataSet()", "GetDataSet") }; MyEvaluator eval = new MyEvaluator(items); Console.WriteLine("TestStatic0: {0}", eval.EvaluateInt("GetNumber")); Console.WriteLine("TestStatic1: {0}", eval.EvaluateString("GetString")); Console.WriteLine("TestStatic2: {0}", eval.EvaluateBool("GetBool")); Console.WriteLine("TestStatic3: {0}", eval.Evaluate("GetDataSet")); Console.ReadLine(); } }