首页 > 代码库 > using System.Reflection;
using System.Reflection;
基础代码：
1 public interface IDBHelper 2 { 3 void Query(); 4 } 5 public class DBHelper : IDBHelper 6 { 7 public int Id { get; set; } 8 public string Name { get; set; } 9 10 public DBHelper()11 {12 //Console.WriteLine("这里是{0}的无参构造函数", this.GetType().FullName);13 }14 15 public void Query()16 {17 //Console.WriteLine("这里是{0}的Query", this.GetType().FullName);18 }19 20 }
1. 反射加载dll，读取module
动态加载:
1 Assembly assembly = Assembly.Load("当前路径下的dll文件");// 默认加载当前路径的dll文件，不需要后缀2 Assembly assembly1 = Assembly.LoadFile("完整路径");// 必须是完整路径-需要后缀.dll3 Assembly assembly2 = Assembly.LoadFrom("当前路径|或者是完整路径");// 可以是当前路径 也可以是完整路径-需要后缀.dll
2. 读取module、类、方法
1 Console.WriteLine("************GetModules**********"); 2 foreach (var item in assembly.GetModules()) 3 { 4 Console.WriteLine(item.FullyQualifiedName); 5 } 6 foreach (var item in assembly.GetTypes()) 7 { 8 Console.WriteLine(item.FullName); 9 }10 Type typeDBHelper = assembly.GetType("Ruanmou.DB.Sqlserver.DBHelper");//2 获取类型-指定名称获取类型11 foreach (var item in typeDBHelper.GetConstructors())12 {13 Console.WriteLine(item.Name);14 }15 foreach (var item in typeDBHelper.GetProperties())16 {17 Console.WriteLine(item.Name);18 }19 foreach (var item in typeDBHelper.GetMethods())20 {21 Console.WriteLine(item.Name);22 }23 foreach (var item in typeDBHelper.GetFields())24 {25 Console.WriteLine(item.Name);26 }
3.简单工厂：
配置文件：
1 <?xml version="1.0" encoding="utf-8" ?>2 <configuration>3 <startup>4 <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.5" />5 </startup>6 <appSettings>7 <add key="IDBHelper" value=http://www.mamicode.com/"Ruanmou.DB.Sqlserver.DBHelper,Ruanmou.DB.Sqlserver"/>8 </appSettings>9 </configuration>
1 public class SimpleFactory 2 { 3 private static string IDBHelperConfig = ConfigurationManager.AppSettings["IDBHelper"]; 4 5 public static IDBHelper CreateDBHelper() 6 { 7 string dllName = IDBHelperConfig.Split(‘,‘)[1]; 8 string className = IDBHelperConfig.Split(‘,‘)[0]; 9 10 Assembly assembly = Assembly.Load(dllName);11 Type type = assembly.GetType(className);12 object oObject = Activator.CreateInstance(type);13 return (IDBHelper)oObject;14 15 }16 }
对比一下,个人感觉就是封装了一下.不过用起来很方便的啦！
Console.WriteLine("**************************************************"); { object oDBHelper = Activator.CreateInstance(typeDBHelper);// 创建对象 IDBHelper dbHelperReflection = (IDBHelper)oDBHelper; dbHelperReflection.Query(); //简单工厂 IDBHelper dbHelperFactory = SimpleFactory.CreateDBHelper(); dbHelperFactory.Query(); }
4.反射创建对象,反射+简单工厂+配置文件. ------------------ 破坏单例 创建泛型
1 namespace Ruanmou.DB.Sqlserver 2 { 3 /// <summary> 4 /// 反射测试类 5 /// </summary> 6 public class ReflectionTest 7 { 8 public int Id { get; set; } 9 public string Name { get; set; }10 11 public string Field = null;12 public static string FieldStatic = null;13 14 15 #region 构造函数16 public ReflectionTest()17 {18 Console.WriteLine("这里是{0}无参数构造函数", this.GetType());19 }20 21 public ReflectionTest(string name)22 {23 Console.WriteLine("这里是{0} 有参数构造函数", this.GetType());24 }25 26 public ReflectionTest(int id, string name)27 {28 Console.WriteLine("这里是{0} 有参数构造函数", this.GetType());29 }30 #endregion31 32 public static void ShowStatic(string name)33 {34 Console.WriteLine("这里是{0}的ShowStatic", typeof(ReflectionTest));35 }36 37 public void ShowGeneric<T>(string name)38 {39 Console.WriteLine("这里是{0}的ShowStatic T={1}", this.GetType(), typeof(T));40 }41 42 public void Show1()43 {44 Console.WriteLine("这里是{0}的Show1", this.GetType());45 }46 47 public void Show2(int id)48 {49 50 Console.WriteLine("这里是{0}的Show2", this.GetType());51 }52 53 public void Show3()54 {55 Console.WriteLine("这里是{0}的Show3_1", this.GetType());56 }57 58 public void Show3(int id, string name)59 {60 Console.WriteLine("这里是{0}的Show3", this.GetType());61 }62 63 public void Show3(string name, int id)64 {65 Console.WriteLine("这里是{0}的Show3_2", this.GetType());66 }67 68 public void Show3(int id)69 {70 71 Console.WriteLine("这里是{0}的Show3_3", this.GetType());72 }73 74 public void Show3(string name)75 {76 77 Console.WriteLine("这里是{0}的Show3_4", this.GetType());78 }79 80 private void Show4(string name)81 {82 Console.WriteLine("这里是{0}的Show4", this.GetType());83 }84 85 }86 }
1 /// <summary> 2 /// 单例模式 3 /// </summary> 4 public sealed class Singleton 5 { 6 private Singleton() 7 { 8 Console.WriteLine("初始化一次"); 9 }10 11 private static Singleton Instance = new Singleton();12 13 public static Singleton CreateInstance()14 {15 return Instance;16 }17 }
单例就是一个类只有一个实例
对构造函数的调用:
反射创建实例时,要指定类型.然后再指定构造函数的参数.
1 { 2 Console.WriteLine("**************带参数的构造函数****************"); 3 Type typeTest = assembly.GetType("Ruanmou.DB.Sqlserver.ReflectionTest"); 4 foreach (var item in typeTest.GetConstructors()) 5 { 6 Console.WriteLine(item.Name); 7 } 8 Activator.CreateInstance(typeTest); 9 Activator.CreateInstance(typeTest, "demon");10 Activator.CreateInstance(typeTest, 11, "限量版(397-限量版)");11 //Activator.CreateInstance(typeTest, "限量版(397-限量版)", 11);---这里调用时将两个不同类型的参数位置放置错误,导致错误.所以注释了.12 13 //该反射破坏了单例14 Type typeSingleton = assembly.GetType("Ruanmou.DB.Sqlserver.Singleton");15 Activator.CreateInstance(typeSingleton, true);16 Activator.CreateInstance(typeSingleton, true);17 //泛型18 Type typeGeneric = assembly.GetType("Ruanmou.DB.Sqlserver.GenericClass`1");19 typeGeneric = typeGeneric.MakeGenericType(typeof(int));//反射调用泛型时指定类型的方法20 Activator.CreateInstance(typeGeneric);21 }
5. 反射调用实例方法、静态方法、重载方法 -------------调用私有方法 调用泛型方法(这个666)
1 Console.WriteLine("**************反射调用实例方法****************"); 2 Type typeTest = assembly.GetType("Ruanmou.DB.Sqlserver.ReflectionTest"); 3 object oTest = Activator.CreateInstance(typeTest); 4 5 foreach (var item in typeTest.GetMethods()) 6 { 7 Console.WriteLine(item.Name); 8 } 9 {10 MethodInfo method = typeTest.GetMethod("Show1");11 method.Invoke(oTest, null);12 }13 {14 MethodInfo method = typeTest.GetMethod("Show2");15 method.Invoke(oTest, new object[] { 11 });//调用方法时第一个参数指定实例16 }17 {18 MethodInfo method = typeTest.GetMethod("ShowStatic");19 method.Invoke(null, new object[] { "KOBE→Bryant" });//静态方法的第一个参数为null-是因为静态方法的调用不需要指定实例20 }
//以下对应不同的重载方法:21 {22 MethodInfo method = typeTest.GetMethod("Show3", new Type[] { });23 method.Invoke(oTest, null);24 }25 {26 MethodInfo method = typeTest.GetMethod("Show3", new Type[] { typeof(int) });27 method.Invoke(oTest, new object[] { 11 });28 }29 {30 MethodInfo method = typeTest.GetMethod("Show3", new Type[] { typeof(string) });31 method.Invoke(oTest, new object[] { "限量版(397-限量版)" });32 }33 {34 MethodInfo method = typeTest.GetMethod("Show3", new Type[] { typeof(string), typeof(int) });35 method.Invoke(oTest, new object[] { "书呆熊@拜仁", 22 });36 }37 {38 MethodInfo method = typeTest.GetMethod("Show3", new Type[] { typeof(int), typeof(string) });39 method.Invoke(oTest, new object[] { 33, "不懂微软" });40 }
//除了参数,指定控制绑定和由反射执行的成员和类型搜索方法的标志,可以调用私有方法.41 {42 MethodInfo method = typeTest.GetMethod("Show4", BindingFlags.Instance | BindingFlags.NonPublic);43 method.Invoke(oTest, new object[] { "有木有" });44 }45 {46 MethodInfo method = typeTest.GetMethod("ShowGeneric");47 method = method.MakeGenericMethod(typeof(string));48 method.Invoke(oTest, new object[] { "有木有" });49 }
6. 反射字段和属性，分别获取值和设置值
1 Console.WriteLine("**************反射字段和属性****************"); 2 ReflectionTest test = new ReflectionTest(); 3 test.Id = 11; 4 test.Name = "妙为"; 5 6 Type typeTest = assembly.GetType("Ruanmou.DB.Sqlserver.ReflectionTest"); 7 object oTest = Activator.CreateInstance(typeTest); 8 //foreach (var item in typeTest.GetFields(BindingFlags.Instance | BindingFlags.Static | BindingFlags.Public)) 9 //{10 // Console.WriteLine(item.Name);11 //}12 foreach (var prop in typeTest.GetProperties())13 {14 Console.WriteLine(prop.GetValue(oTest));15 Console.WriteLine(prop.Name);16 if (prop.Name.Equals("Id"))17 {18 prop.SetValue(oTest, 22);19 }20 else if (prop.Name.Equals("Name"))21 {22 prop.SetValue(oTest, "Bond(331-object)");23 }24 25 Console.WriteLine(prop.GetValue(oTest));26 }
7. 反射的好处和局限 好处就是动态
1 { 2 Stopwatch watch = new Stopwatch(); 3 watch.Start(); 4 for (int i = 0; i < 100000; i++) 5 { 6 DBHelper dbHelper = new DBHelper(); 7 dbHelper.Id = 1; 8 dbHelper.Name = "仗劍走天涯"; 9 dbHelper.Query();10 }11 watch.Stop();12 Console.WriteLine("普通方式花费{0}ms", watch.ElapsedMilliseconds);13 }14 {15 Stopwatch watch = new Stopwatch();16 watch.Start();17 for (int i = 0; i < 100000; i++)18 {19 Assembly assemblyTest = Assembly.Load("Ruanmou.DB.Sqlserver");20 21 Type typeTest = assemblyTest.GetType("Ruanmou.DB.Sqlserver.DBHelper");22 object oTest = Activator.CreateInstance(typeTest);23 24 foreach (var prop in typeTest.GetProperties())25 {26 if (prop.Name.Equals("Id"))27 {28 prop.SetValue(oTest, 1);29 }30 else if (prop.Name.Equals("Name"))31 {32 prop.SetValue(oTest, "仗劍走天涯");33 }34 }35 MethodInfo method = typeTest.GetMethod("Query");36 method.Invoke(oTest, null);37 }38 watch.Stop();39 Console.WriteLine("反射方式花费{0}ms", watch.ElapsedMilliseconds);40 }
局限：避开了编译器的检查,运行时错误才会暴露出来.(如果有的话)
性能损耗
using System.Reflection;
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