注：這里對(duì)于轉(zhuǎn)換成Demical,Float類(lèi)型暫時(shí)不成立(因?yàn)槿粢D(zhuǎn)成功，表達(dá)式里必須含有如Decimal: 0.2m, Float: 2.0f 這兩個(gè)暫時(shí)轉(zhuǎn)換不成功)
/// <summary>
/// 本類(lèi)用來(lái)將字符串轉(zhuǎn)為可執(zhí)行文本并執(zhí)行
/// 從別處復(fù)制，勿隨意更改！
/// </summary>
public class Evaluator
{
#region 構(gòu)造函數(shù)
/// <summary>
/// 可執(zhí)行串的構(gòu)造函數(shù)
/// </summary>
/// <param name="items">
/// 可執(zhí)行字符串?dāng)?shù)組
/// </param>
public Evaluator(EvaluatorItem[] items)
{
ConstructEvaluator(items); //調(diào)用解析字符串構(gòu)造函數(shù)進(jìn)行解析
}
/// <summary>
/// 可執(zhí)行串的構(gòu)造函數(shù)
/// </summary>
/// <param name="returnType">返回值類(lèi)型</param>
/// <param name="expression">執(zhí)行表達(dá)式</param>
/// <param name="name">執(zhí)行字符串名稱(chēng)</param>
public Evaluator(Type returnType, string expression, string name)
{
//創(chuàng)建可執(zhí)行字符串?dāng)?shù)組
EvaluatorItem[] items = { new EvaluatorItem(returnType, expression, name) };
ConstructEvaluator(items); //調(diào)用解析字符串構(gòu)造函數(shù)進(jìn)行解析
}
/// <summary>
/// 可執(zhí)行串的構(gòu)造函數(shù)
/// </summary>
/// <param name="item">可執(zhí)行字符串項(xiàng)</param>
public Evaluator(EvaluatorItem item)
{
EvaluatorItem[] items = { item };//將可執(zhí)行字符串項(xiàng)轉(zhuǎn)為可執(zhí)行字符串項(xiàng)數(shù)組
ConstructEvaluator(items); //調(diào)用解析字符串構(gòu)造函數(shù)進(jìn)行解析
}
/// <summary>
/// 解析字符串構(gòu)造函數(shù)
/// </summary>
/// <param name="items">待解析字符串?dāng)?shù)組</param>
private void ConstructEvaluator(EvaluatorItem[] items)
{
//創(chuàng)建C#編譯器實(shí)例
ICodeCompiler comp = (new CSharpCodeProvider().CreateCompiler());
//編譯器的傳入?yún)?shù)
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; //不生成可執(zhí)行文件
cp.GenerateInMemory = true; //在內(nèi)存中運(yùn)行
StringBuilder code = new StringBuilder(); //創(chuàng)建代碼串
/*
* 添加常見(jiàn)且必須的引用字符串
*/
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 EvalGuy { \n"); //生成代碼的命名空間為EvalGuy，和本代碼一樣
code.Append(" public class _Evaluator { \n"); //產(chǎn)生 _Evaluator 類(lèi)，所有可執(zhí)行代碼均在此類(lèi)中運(yùn)行
foreach (EvaluatorItem item in items) //遍歷每一個(gè)可執(zhí)行字符串項(xiàng)
{
code.AppendFormat(" public {0} {1}() ", //添加定義公共函數(shù)代碼
item.ReturnType.Name, //函數(shù)返回值為可執(zhí)行字符串項(xiàng)中定義的返回值類(lèi)型
item.Name); //函數(shù)名稱(chēng)為可執(zhí)行字符串項(xiàng)中定義的執(zhí)行字符串名稱(chēng)
code.Append("{ "); //添加函數(shù)開(kāi)始括號(hào)
code.AppendFormat("return ({0});", item.Expression);//添加函數(shù)體，返回可執(zhí)行字符串項(xiàng)中定義的表達(dá)式的值
code.Append("}\n"); //添加函數(shù)結(jié)束括號(hào)
}
code.Append("} }"); //添加類(lèi)結(jié)束和命名空間結(jié)束括號(hào)
//得到編譯器實(shí)例的返回結(jié)果
CompilerResults cr = comp.CompileAssemblyFromSource(cp, code.ToString());
if (cr.Errors.HasErrors) //如果有錯(cuò)誤
{
StringBuilder error = new StringBuilder(); //創(chuàng)建錯(cuò)誤信息字符串
error.Append("編譯有錯(cuò)誤的表達(dá)式: "); //添加錯(cuò)誤文本
foreach (CompilerError err in cr.Errors) //遍歷每一個(gè)出現(xiàn)的編譯錯(cuò)誤
{
error.AppendFormat("{0}\n", err.ErrorText); //添加進(jìn)錯(cuò)誤文本，每個(gè)錯(cuò)誤后換行
}
throw new Exception("編譯錯(cuò)誤: " + error.ToString());//拋出異常
}
Assembly a = cr.CompiledAssembly; //獲取編譯器實(shí)例的程序集
_Compiled = a.CreateInstance("EvalGuy._Evaluator"); //通過(guò)程序集查找并聲明 EvalGuy._Evaluator 的實(shí)例
}
#endregion
#region 公有成員
/// <summary>
/// 執(zhí)行字符串并返回整型值
/// </summary>
/// <param name="name">執(zhí)行字符串名稱(chēng)</param>
/// <returns>執(zhí)行結(jié)果</returns>
public int EvaluateInt(string name)
{
return (int)Evaluate(name);
}
/// <summary>
/// 執(zhí)行字符串并返回金額值
/// </summary>
/// <param name="name">執(zhí)行字符串名稱(chēng)</param>
/// <returns>執(zhí)行結(jié)果</returns>
public double EvaluateDouble(string name)
{
return (double)Evaluate(name);
}
/// <summary>
/// 執(zhí)行字符串并返回字符串型值
/// </summary>
/// <param name="name">執(zhí)行字符串名稱(chēng)</param>
/// <returns>執(zhí)行結(jié)果</returns>
public string EvaluateString(string name)
{
return (string)Evaluate(name);
}
/// <summary>
/// 執(zhí)行字符串并返回布爾型值
/// </summary>
/// <param name="name">執(zhí)行字符串名稱(chēng)</param>
/// <returns>執(zhí)行結(jié)果</returns>
public bool EvaluateBool(string name)
{
return (bool)Evaluate(name);
}
/// <summary>
/// 執(zhí)行字符串并返 object 型值
/// </summary>
/// <param name="name">執(zhí)行字符串名稱(chēng)</param>
/// <returns>執(zhí)行結(jié)果</returns>
public object Evaluate(string name)
{
MethodInfo mi = _Compiled.GetType().GetMethod(name);//獲取 _Compiled 所屬類(lèi)型中名稱(chēng)為 name 的方法的引用
return mi.Invoke(_Compiled, null); //執(zhí)行 mi 所引用的方法
}
#endregion
#region 靜態(tài)成員
/// <summary>
/// 執(zhí)行表達(dá)式并返回整型類(lèi)型值
/// </summary>
/// <param name="code">要執(zhí)行的表達(dá)式</param>
/// <returns>運(yùn)算結(jié)果</returns>
public static int EvaluateToInteger(string code)
{
Evaluator eval = new Evaluator(typeof(int), code, staticMethodName);//生成 Evaluator 類(lèi)的對(duì)像
return (int)eval.Evaluate(staticMethodName); //執(zhí)行并返回整型數(shù)據(jù)
}
/// <summary>
/// 執(zhí)行表達(dá)式并返回金額類(lèi)型值
/// </summary>
/// <param name="code">要執(zhí)行的表達(dá)式</param>
/// <returns>運(yùn)算結(jié)果</returns>
public static double EvaluateToDouble(string code)
{
Evaluator eval = new Evaluator(typeof(double), code, staticMethodName);//生成 Evaluator 類(lèi)的對(duì)像
return (double)eval.Evaluate(staticMethodName); //執(zhí)行并返回整型數(shù)據(jù)
}
/// <summary>
/// 執(zhí)行表達(dá)式并返回字符串型值
/// </summary>
/// <param name="code">要執(zhí)行的表達(dá)式</param>
/// <returns>運(yùn)算結(jié)果</returns>
public static string EvaluateToString(string code)
{
Evaluator eval = new Evaluator(typeof(string), code, staticMethodName);//生成 Evaluator 類(lèi)的對(duì)像
return (string)eval.Evaluate(staticMethodName); //執(zhí)行并返回字符串型數(shù)據(jù)
}
/// <summary>
/// 執(zhí)行表達(dá)式并返回布爾型值
/// </summary>
/// <param name="code">要執(zhí)行的表達(dá)式</param>
/// <returns>運(yùn)算結(jié)果</returns>
public static bool EvaluateToBool(string code)
{
Evaluator eval = new Evaluator(typeof(bool), code, staticMethodName);//生成 Evaluator 類(lèi)的對(duì)像
return (bool)eval.Evaluate(staticMethodName); //執(zhí)行并返回布爾型數(shù)據(jù)
}
/// <summary>
/// 執(zhí)行表達(dá)式并返回 object 型值
/// </summary>
/// <param name="code">要執(zhí)行的表達(dá)式</param>
/// <returns>運(yùn)算結(jié)果</returns>
public static object EvaluateToObject(string code)
{
Evaluator eval = new Evaluator(typeof(object), code, staticMethodName);//生成 Evaluator 類(lèi)的對(duì)像
return eval.Evaluate(staticMethodName); //執(zhí)行并返回 object 型數(shù)據(jù)
}
#endregion
#region 私有成員
/// <summary>
/// 靜態(tài)方法的執(zhí)行字符串名稱(chēng)
/// </summary>
private const string staticMethodName = "__foo";
/// <summary>
/// 用于動(dòng)態(tài)引用生成的類(lèi)，執(zhí)行其內(nèi)部包含的可執(zhí)行字符串
/// </summary>
object _Compiled = null;
#endregion
}
/// <summary>
/// 可執(zhí)行字符串項(xiàng)（即一條可執(zhí)行字符串）
/// </summary>
public class EvaluatorItem
{
/// <summary>
/// 返回值類(lèi)型
/// </summary>
public Type ReturnType;
/// <summary>
/// 執(zhí)行表達(dá)式
/// </summary>
public string Expression;
/// <summary>
/// 執(zhí)行字符串名稱(chēng)
/// </summary>
public string Name;
/// <summary>
/// 可執(zhí)行字符串項(xiàng)構(gòu)造函數(shù)
/// </summary>
/// <param name="returnType">返回值類(lèi)型</param>
/// <param name="expression">執(zhí)行表達(dá)式</param>
/// <param name="name">執(zhí)行字符串名稱(chēng)</param>
public EvaluatorItem(Type returnType, string expression, string name)
{
ReturnType = returnType;
Expression = expression;
Name = name;
}
//調(diào)用方法：注意引用EvalGuy命名空間：
#region
//Console.WriteLine("Test0: {0}", Evaluator.EvaluateToInteger("(30 + 4) * 2"));
//Console.WriteLine("Test1: {0}", Evaluator.EvaluateToString("\"Hello \" + \"There\""));
//Console.WriteLine("Test2: {0}", Evaluator.EvaluateToBool("30 == 40"));
//Console.WriteLine("Test3: {0}", Evaluator.EvaluateToObject("new DataSet()"));
//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")
// };
//Evaluator eval = new Evaluator(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"));
#endregion
}
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