C#反射机制(转)
一:反射的定义
审查元数据并收集关于它的类型信息的能力。元数据(编译以后的最基本数据单元)就是一大堆的表,当编译程序集或者模块时,编译器会创建一个类定义表,一个字段定义表,和一个方法定义表等。
System.reflection命名空间包含的几个类,允许你反射(解析)这些元数据表的代码
System.Reflection.Assembly
System.Reflection.MemberInfo
System.Reflection.EventInfo
System.Reflection.FieldInfo
System.Reflection.MethodBase
System.Reflection.ConstructorInfo
System.Reflection.MethodInfo
System.Reflection.PropertyInfo
System.Type
层次模型:
二:获取类型信息:
1 class MyClass 2 { 3 public string m; 4 public void test() { } 5 public int MyProperty { get; set; } 6 } 7 8 //获取类型信息 9 protected void Button1_Click(object sender, EventArgs e) 10 { 11 Type type = typeof(MyClass); 12 Response.Write("类型名:" + type.Name); 13 Response.Write("<br/>"); 14 Response.Write("类全名:" + type.FullName); 15 Response.Write("<br/>"); 16 Response.Write("命名空间名:" + type.Namespace); 17 Response.Write("<br/>"); 18 Response.Write("程序集名:" + type.Assembly); 19 Response.Write("<br/>"); 20 Response.Write("模块名:" + type.Module); 21 Response.Write("<br/>"); 22 Response.Write("基类名:" + type.BaseType); 23 Response.Write("<br/>"); 24 Response.Write("是否类:" + type.IsClass); 25 Response.Write("<br/>"); 26 Response.Write("类的公共成员:"); 27 Response.Write("<br/>"); 28 MemberInfo[] memberInfos = type.GetMembers();//得到所有公共成员 29 foreach (var item in memberInfos) 30 { 31 Response.Write(string.Format("{0}:{1}", item.MemberType, item)); 32 Response.Write("<br/>"); 33 } 34 }
三:获取程序集信息
protected void Button2_Click( object sender, EventArgs e) { //获取当前执行代码的程序集 Assembly assem = Assembly.GetExecutingAssembly(); Response.Write( "程序集全名:" +assem.FullName); Response.Write( "<br/>" ); Response.Write( "程序集的版本:" +assem.GetName().Version); Response.Write( "<br/>" ); Response.Write( "程序集初始位置:" +assem.CodeBase); Response.Write( "<br/>" ); Response.Write( "程序集位置:" +assem.Location); Response.Write( "<br/>" ); Response.Write( "程序集入口:" +assem.EntryPoint); Response.Write( "<br/>" ); Type[] types = assem.GetTypes(); Response.Write( "程序集下包含的类型:" ); foreach ( var item in types) { Response.Write( "<br/>" ); Response.Write( "类:" +item.Name); } }<br> |
四:反射调用方法
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protected void Page_Load( object sender, EventArgs e) { System.Reflection.Assembly ass = Assembly.LoadFrom(AppDomain.CurrentDomain.BaseDirectory+ "bin\\WebApplication1.dll" ); //加载DLL System.Type t = ass.GetType( "WebApplication1.MainPage" ); //获得类型 string name= typeof (MainPage).AssemblyQualifiedName; System.Type t1 = Type.GetType(name); System.Type t2 = typeof (MainPage); object o = System.Activator.CreateInstance(t); //创建实例 System.Reflection.MethodInfo mi = t.GetMethod( "RunJs1" ); //获得方法 mi.Invoke(o, new object [] { this .Page, "alert('测试反射机制')" }); //调用方法 System.Reflection.MethodInfo mi1 = t.GetMethod( "RunJs" ); mi1.Invoke(t, new object [] { this .Page, "alert('测试反射机制1')" }); //调用方法 }<br> |
五:反射调用用户/自定义控件
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protected override void OnInit(EventArgs e) { //生成控件 CreateControl(); base .OnInit(e); } private void CreateControl() { Table tb = new Table(); TableRow dr = new TableRow(); TableCell cell = new TableCell(); Control c = <span style= "color: #ff0000;" >LoadControl( "WebUserControl1.ascx" ); </span> cell.Controls.Add(c); dr.Cells.Add(cell); tb.Rows.Add(dr); this .PlaceHolder1.Controls.Add(tb); } protected void Button1_Click( object sender, EventArgs e) { foreach (TableRow tr in PlaceHolder1.Controls[0].Controls) { foreach (TableCell tc in tr.Controls) { foreach (Control ctl in tc.Controls) { if (ctl is UserControl) { Type type = ctl.GetType(); System.Reflection.MethodInfo methodInfo = type.GetMethod( "GetResult" ); string selectedValue = string .Concat(methodInfo.Invoke(ctl, new object [] { })); Response.Write(selectedValue); break ; } } } } }<br> |
六:反射实现工厂模式
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public partial class 反射 : System.Web.UI.Page { protected void Page_Load( object sender, EventArgs e) { string typeName = typeof (TestClass).AssemblyQualifiedName; ITestInterface iface = RawGenericFactory.Create<ITestInterface>(typeName); string result = iface.doSomething(); Response.Write(result); } } public static class RawGenericFactory { public static T Create<T>( string typeName) { //Activator.CreateInstance 反射 根据程序集创建借口或者类 //Type.GetType() 根据名称获得程序集信息 //typeof(ConcertProduct).AssemblyQualifiedName //_iproduct.GetType().AssemblyQualifiedName return (T)Activator.CreateInstance(Type.GetType(typeName)); } } public interface ITestInterface { string doSomething(); } public class TestClass : ITestInterface { public int Id { get ; set ; } public override string ToString() { return Id.ToString(); } public string doSomething() { return "ok" ; } }<br> |
七:自定义ORM框架
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[Orm.Table( "TestORM" )] public class TestORM { [Orm.Colum( "Id" ,DbType.Int32)] public int Id { get ; set ; } [Orm.Colum( "UserName" , DbType.String)] public string UserName { get ; set ; } [Orm.Colum( "Password" , DbType.String)] public string Password { get ; set ; } [Orm.Colum( "CreatedTime" , DbType.DateTime)] public DateTime CreatedTime { get ; set ; } } protected void Button3_Click( object sender, EventArgs e) { TestORM t = new TestORM() { Id=1, UserName= "binfire" , Password= "xxx" , CreatedTime=DateTime.Now }; Orm.OrmHelp h= new Orm.OrmHelp(); h.Insert(t); } namespace Orm { [AttributeUsageAttribute(AttributeTargets.Class, Inherited = false , AllowMultiple = false )] public class TableAttribute : Attribute { //保存表名的字段 private string _tableName; public TableAttribute() { } public TableAttribute( string tableName) { this ._tableName = tableName; } /// /// 映射的表名(表的全名:模式名.表名) /// public string TableName { set { this ._tableName = value; } get { return this ._tableName; } } } [AttributeUsageAttribute(AttributeTargets.Property, Inherited = false , AllowMultiple = false )] public class ColumAttribute : Attribute { private string _columName; private DbType _dbType; public ColumAttribute() { } public ColumAttribute( string columName) : this () { this ._columName = columName; } public ColumAttribute( string columName, DbType dbType) : this (columName) { this ._dbType = dbType; } //列名 public virtual string ColumName { set { this ._columName = value; } get { return this ._columName; } } //描述一些特殊的数据库类型 public DbType DbType { get { return _dbType; } set { _dbType = value; } } } public class OrmHelp { public void Insert( object table) { Type type = table.GetType(); //定义一个字典来存放表中字段和值的对应序列 Dictionary< string , string > columValue = new Dictionary< string , string >(); StringBuilder SqlStr = new StringBuilder(); SqlStr.Append( "insert into " ); //得到表名子 TableAttribute temp = (TableAttribute)type.GetCustomAttributes( typeof (TableAttribute), false ).First(); SqlStr.Append(temp.TableName); SqlStr.Append( "(" ); PropertyInfo[] Propertys = type.GetProperties(); foreach ( var item in Propertys) { object [] attributes = item.GetCustomAttributes( false ); foreach ( var item1 in attributes) { //获得相应属性的值 string value = table.GetType().InvokeMember(item.Name, System.Reflection.BindingFlags.GetProperty, null , table, null ).ToString(); ColumAttribute colum = item1 as ColumAttribute; if (colum != null ) { columValue.Add(colum.ColumName, value); } } } //拼插入操作字符串 foreach ( var item in columValue) { SqlStr.Append(item.Key); SqlStr.Append( "," ); } SqlStr.Remove(SqlStr.Length - 1, 1); SqlStr.Append( ") values('" ); foreach ( var item in columValue) { SqlStr.Append(item.Value); SqlStr.Append( "','" ); } SqlStr.Remove(SqlStr.Length - 2, 2); SqlStr.Append( ")" ); HttpContext.Current.Response.Write(SqlStr.ToString()); } } } |