C# 反射Reflection——反射反射程序員的快樂
阿新 • • 發佈：2019-03-12
*** 文件夾 指定字段 完整路徑 eric mea write adf getc 一、什麽是反射
反射Reflection:System.Reflection，是.Net Framework提供的一個幫助類庫，可以讀取並使用metadata。
反射是無處不在的，MVC-Asp.Net-ORM-IOC-AOP 幾乎所有的框架都離不開反射
如下圖是程序執行的過程，高級語言經過編譯器編譯得到dll/exe文件，這裏的文件可以跨平臺使用，編譯後的文件中其實包括了metadata元數據（數據清單，描述了DLL/exe裏面的各種信息）和IL（也是一種面向對象語言，但是不太好閱讀）在經過CLR/JIT編譯得到可以被計算機所執行的機器碼。
二、反射的使用
一）反射動態加載程序集
二、反射的使用
一）反射動態加載程序集
Assembly assembly1 = Assembly.LoadFrom(@"DB.MySql.dll");//當前路徑 Assembly assembly2 = Assembly.LoadFile(@"D:\ruanmou\MyReflection\bin\Debug\DB.MySql.dll");//dll、exe文件完整路徑 Assembly assembly3 = Assembly.Load(@"DB.MySql");//dll、exe名稱 dll/exe需要拷貝至程序bin文件夾下View Code
二）簡單工廠生產對應實體
/// <summary> /// 簡單工廠生產對應實體 /// </summary> /// <returns></returns> public static T CreateInstance<T>() { Assembly assembly = Assembly.Load(ConfigurationManager.AppSettings["DalDllName"]);//加載dll Type dalType = assembly.GetType(ConfigurationManager.AppSettings["View CodeDalTypeName"]);//獲取類型 return (T)Activator.CreateInstance(dalType);//創建對象 //var newType = dalType.MakeGenericType(typeof(T));//獲取泛型類型 //return (T)Activator.CreateInstance(newType);創建泛型類型對象 }
三）常用方法
Type[] types= assembly.GetTypes();//獲取程序集所有類型 Type type= assembly.GetType("TypeName");//獲取指定類型 MethodInfo[] methods= type.GetMethods();//獲取所有方法 MethodInfo method= type.GetMethod("methodName");//獲取指定方法 PropertyInfo[] propertys= type.GetProperties();//獲取所有屬性 PropertyInfo property = type.GetProperty("propertyName");//獲取指定屬性 FieldInfo[] fields= type.GetFields();//獲取所有字段 FieldInfo field = type.GetField("fieldName");//獲取指定字段 Attribute attribute = type.GetCustomAttribute(typeof(DisplayNameAttribute));//獲取指定特性View Code
反射調用多參數構造函數，方法
/// <summary> /// 反射測試類 /// </summary> public class ReflectionTest { #region Identity /// <summary> /// 無參構造函數 /// </summary> public ReflectionTest() { Console.WriteLine("這裏是{0}無參數構造函數", this.GetType()); } /// <summary> /// 帶參數構造函數 /// </summary> /// <param name="name"></param> public ReflectionTest(string name) { Console.WriteLine("這裏是{0} 有參數構造函數", this.GetType()); } public ReflectionTest(int id) { Console.WriteLine("這裏是{0} 有參數構造函數", this.GetType()); } #endregion #region Method /// <summary> /// 無參方法 /// </summary> public void Show1() { Console.WriteLine("這裏是{0}的Show1", this.GetType()); } /// <summary> /// 有參數方法 /// </summary> /// <param name="id"></param> public void Show2(int id) { Console.WriteLine("這裏是{0}的Show2", this.GetType()); } /// <summary> /// 重載方法之一 /// </summary> /// <param name="id"></param> /// <param name="name"></param> public void Show3(int id, string name) { Console.WriteLine("這裏是{0}的Show3", this.GetType()); } /// <summary> /// 重載方法之二 /// </summary> /// <param name="name"></param> /// <param name="id"></param> public void Show3(string name, int id) { Console.WriteLine("這裏是{0}的Show3_2", this.GetType()); } /// <summary> /// 重載方法之三 /// </summary> /// <param name="id"></param> public void Show3(int id) { Console.WriteLine("這裏是{0}的Show3_3", this.GetType()); } /// <summary> /// 重載方法之四 /// </summary> /// <param name="name"></param> public void Show3(string name) { Console.WriteLine("這裏是{0}的Show3_4", this.GetType()); } /// <summary> /// 重載方法之五 /// </summary> public void Show3() { Console.WriteLine("這裏是{0}的Show3_1", this.GetType()); } /// <summary> /// 私有方法 /// </summary> /// <param name="name"></param> private void Show4(string name) { Console.WriteLine("這裏是{0}的Show4", this.GetType()); } /// <summary> /// 靜態方法 /// </summary> /// <param name="name"></param> public static void Show5(string name) { Console.WriteLine("這裏是{0}的Show5", typeof(ReflectionTest)); } #endregion }View Code
Assembly assembly = Assembly.Load("Ruanmou.DB.SqlServer"); Type type = assembly.GetType("Ruanmou.DB.SqlServer.ReflectionTest"); object oTest = Activator.CreateInstance(type);//反射調用無參數構造函數 object oTest2 = Activator.CreateInstance(type, new object[] { 123 });//反射調用一個int類型參數構造函數 foreach (var method in type.GetMethods()) { Console.WriteLine(method.Name); foreach (var parameter in method.GetParameters())//獲取方法參數 { Console.WriteLine($"{parameter.Name} {parameter.ParameterType}"); } } { ReflectionTest reflection = new ReflectionTest(); reflection.Show1(); } { MethodInfo method = type.GetMethod("Show1"); //if() method.Invoke(oTest, null);//oTest調用無參數方法 } { MethodInfo method = type.GetMethod("Show2"); method.Invoke(oTest, new object[] { 123 });//oTest調用一個int類型參數方法 } { MethodInfo method = type.GetMethod("Show3", new Type[] { }); method.Invoke(oTest, null);//oTest調用無參數重載方法 } { MethodInfo method = type.GetMethod("Show3", new Type[] { typeof(int) }); method.Invoke(oTest, new object[] { 123 });//oTest調用一個int類型參數重載方法 } { MethodInfo method = type.GetMethod("Show5"); method.Invoke(oTest, new object[] { "String" });//靜態方法實例可以要 } { MethodInfo method = type.GetMethod("Show5"); method.Invoke(null, new object[] { "string" });//靜態方法實例也可以不要 }View Code
var method = type.GetMethod("Show4", BindingFlags.Instance | BindingFlags.NonPublic); method.Invoke(oTest, new object[] { "私有方法" });反射調用私有方法
反射調用泛型方法、泛型類
public class GenericClass<T, W, X> { public void Show(T t, W w, X x) { Console.WriteLine("t.type={0},w.type={1},x.type={2}", t.GetType().Name, w.GetType().Name, x.GetType().Name); } } public class GenericMethod { public void Show<T, W, X>(T t, W w, X x) { Console.WriteLine("t.type={0},w.type={1},x.type={2}", t.GetType().Name, w.GetType().Name, x.GetType().Name); } } public class GenericDouble<T> { public void Show<W, X>(T t, W w, X x) { Console.WriteLine("t.type={0},w.type={1},x.type={2}", t.GetType().Name, w.GetType().Name, x.GetType().Name); } }View Code
{ Console.WriteLine("********************GenericMethod********************"); Assembly assembly = Assembly.Load("Ruanmou.DB.SqlServer"); Type type = assembly.GetType("Ruanmou.DB.SqlServer.GenericMethod"); object oGeneric = Activator.CreateInstance(type); //foreach (var item in type.GetMethods()) //{ // Console.WriteLine(item.Name); //} MethodInfo method = type.GetMethod("Show"); var methodNew = method.MakeGenericMethod(new Type[] { typeof(int), typeof(string), typeof(DateTime) }); object oReturn = methodNew.Invoke(oGeneric, new object[] { 123, "test", DateTime.Now }); } { Console.WriteLine("********************GenericMethod+GenericClass********************"); Assembly assembly = Assembly.Load("Ruanmou.DB.SqlServer"); Type type = assembly.GetType("Ruanmou.DB.SqlServer.GenericDouble`1").MakeGenericType(typeof(int)); object oObject = Activator.CreateInstance(type); MethodInfo method = type.GetMethod("Show").MakeGenericMethod(typeof(string), typeof(DateTime)); method.Invoke(oObject, new object[] { 345, "teat", DateTime.Now }); }View Code
反射破壞單例
/// <summary> /// 單例模式：類，能保證在整個進程中只有一個實例 /// </summary> public sealed class Singleton { private static Singleton _Singleton = null; private Singleton() { Console.WriteLine("Singleton被構造"); } static Singleton() { _Singleton = new Singleton(); } public static Singleton GetInstance() { return _Singleton; } }View Code
{ Console.WriteLine("********************Singleton********************"); Singleton singleton1 = Singleton.GetInstance(); //new Singleton(); Singleton singleton2 = Singleton.GetInstance(); Singleton singleton3 = Singleton.GetInstance(); Singleton singleton4 = Singleton.GetInstance(); Singleton singleton5 = Singleton.GetInstance(); Console.WriteLine($"{object.ReferenceEquals(singleton1, singleton5)}"); //反射破壞單例---就是發射調用私有構造函數 Assembly assembly = Assembly.Load("Ruanmou.DB.SqlServer"); Type type = assembly.GetType("Ruanmou.DB.SqlServer.Singleton"); Singleton singletonA = (Singleton)Activator.CreateInstance(type, true); Singleton singletonB = (Singleton)Activator.CreateInstance(type, true); Singleton singletonC = (Singleton)Activator.CreateInstance(type, true); Singleton singletonD = (Singleton)Activator.CreateInstance(type, true); Console.WriteLine($"{object.ReferenceEquals(singletonA, singletonD)}"); }View Code
C# 反射Reflection——反射反射程序員的快樂