类型反射与晚期绑定

在.net中，反射是一个运行库类型发现的过程。使用反射服务，可以得到一个给定*.dll或*.exe程序集所包含的所有类型的列表。

命名空间System.Reflection包含了大量与反射相关的类型，要理解如何使用System.Reflection命名空间编程读取.net元数据，首先要理解System.Type类型

System.Type类型定义了很多成员，可以用来检测某个类型的元数据，它们返回的类型大多数位于System.reflection命名空间中。如：Type.GetMethods()返回一个MethodInfo类型的数组。Type类型的各种成员就不一一列举。

下面是得到Type类型的三种方式：

1.System.Object.GetType()

object obj=new Object();

Type t=obj.GetType();

2.typeOf()

Type t=typeof(Object);

3.System.Type.GetType()

该方法的传入类型的完全限定名

Type t=System.Type.GetType(“System.Object”);

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Reflection;

namespace TypeReflection
{
class Program
{
static void Main(string[] args)
{
//TypeTest();
//AsmTest();
//string displayname = null;
//displayname = "System.Windows.Forms," + "Version=4.0.0.0," + "PublicKeyToken=b77a5c561934e089," + @"Culture=""";
//Assembly asm = Assembly.Load(displayname);
//DisplayTypesinAsm(asm);
ActivatorTest();
}

private static void TypeTest()
{
do
{
Console.WriteLine("Enter a type name or enter Q to quit:");
string str = Console.ReadLine();
if (str.ToUpper() == "Q")
{
break;
}
try
{
Type t = Type.GetType(str);
GetFields(t);
GetProperties(t);
GetMethods(t);
}
catch
{
Console.WriteLine("Sorry,can't find type.");
}
}
while (true);
}
//获取字段
static void GetFields(Type t)
{
if (t != null)
{
Console.WriteLine("*******Fields********");
FieldInfo[] fields = t.GetFields();
foreach(var field in fields)
{
Console.WriteLine("{0} {1}", field.FieldType, field.Name);
}
}
}
//获取属性
static void GetProperties(Type t)
{
if (t != null)
{
Console.WriteLine("*******Properties********");
PropertyInfo[] properties = t.GetProperties();
foreach (var property in properties)
{
Console.WriteLine("{0} {1}", property.PropertyType, property.Name);
}
}
}
//获取方法
static void GetMethods(Type t)
{
if (t != null)
{
Console.WriteLine("*******Methods********");
MethodInfo[] methods = t.GetMethods();
foreach (var method in methods)
{
string str = method.ReturnType.ToString() + " " + method.Name + " (";
foreach (var p in method.GetParameters())
{
str += p.ParameterType + " " + p.Name + ",";
}
str += ");";
Console.WriteLine(str);
}

}
}

static void AsmTest()
{
do
{
Console.WriteLine("Enter a Assembly name or enter Q to quit:");
string str = Console.ReadLine();
if (str.ToUpper() == "Q")
{
break;
}
try
{
Assembly asm = Assembly.LoadFrom(str);//加载程序集
DisplayTypesinAsm(asm);
}
catch
{
Console.WriteLine("Sorry,can't find assembly.");
}
}
while (true);
}
static void DisplayTypesinAsm(Assembly asm)
{
if (asm != null)
{
Console.WriteLine("********Types in Assembly********");
Console.WriteLine("=>{0}", asm.FullName);
var types = from type in asm.GetTypes() where type.IsEnum && type.IsPublic select type;
foreach (var t in types)
{
Console.WriteLine("Type:{0}", t);
}
}
}
//晚期绑定
static void ActivatorTest()
{

try
{
string displayname = null;
displayname = "System.Windows.Forms," + "Version=4.0.0.0," + "PublicKeyToken=b77a5c561934e089," + @"Culture=""";
Assembly asm = Assembly.Load(displayname);//加载程序集
Type t = asm.GetType("System.Windows.Forms.Form");//获取程序集中的类型
object obj= System.Activator.CreateInstance(t);//获取类型的实例
MethodInfo mi = t.GetMethod("ToString");//获取类型的实例方法
object s= mi.Invoke(obj,null);//方法的调用
Console.WriteLine(s);
}
catch(Exception ex)
{
Console.WriteLine(ex.Message);
}
}
}
}