反射-查看类型信息转自MSDN

System.Type 类对于反射起着核心的作用。当反射请求加载的类型时，公共语言运行库将为它创建一个 Type。您可以使用 Type 对象的方法、字段、属性和嵌套类来查找有关该类型的所有信息。

使用 Assembly.GetType 或 Assembly.GetTypes 从尚未加载的程序集中获取 Type 对象，并传入所需类型的名称。使用 Type.GetType 可从已加载的程序集中获取 Type 对象。使用 Module.GetType 和 Module.GetTypes 可获取模块 Type 对象。

注意：

如果想要检查并操作泛型类型和方法，请参见反向和泛型类型和如何：使用反射检查和实例化泛型类型 中提供的其他信息。

下面的示例显示在获取程序集的 Assembly 对象和模块时所必需的语法。

Visual Basic  复制代码 
' Gets the mscorlib assembly in which the object is defined.
            Dim a As Reflection.Assembly = GetType(Object).Module.Assembly
C#  复制代码 
// Gets the mscorlib assembly in which the object is defined.
            Assembly a = typeof(Object).Module.Assembly;

下面的示例说明如何从已加载的程序集中获取 Type 对象。

Visual Basic  复制代码 
' Loads an assembly using its file name.
            Dim a As Reflection.Assembly = Reflection.Assembly.LoadFrom("MyExe.exe")
            ' Gets the type names from the assembly.
            Dim types2 As Type() = a.GetTypes()
            Dim t As Type
            For Each t In  types2
            Console.WriteLine(t.FullName)
            Next t
C#  复制代码 
// Loads an assembly using its file name.
            Assembly a = Assembly.LoadFrom ("MyExe.exe");
            // Gets the type names from the assembly.
            Type [] types2 = a.GetTypes ();
            foreach (Type t in types2)
            {
            Console.WriteLine (t.FullName);
            }

在获取了一个 Type 后，您可以采用许多方法来发现与该类型的成员有关的信息。例如，通过调用 Type..::.GetMembers 方法（该方法将获取对当前类型的每个成员进行描述的一组 MemberInfo 对象），您可以找到有关该类型的所有成员的信息。

您也可以在 Type 类上使用方法，以检索有关按名称指定的一个或多个构造函数、方法、事件、字段或属性的信息。例如，Type..::.GetConstructor 封装当前类的特定构造函数。

如果具有 Type，则可以使用 Type..::.Module 属性来获取一个封装该类型所在模块的对象。使用 Module..::.Assembly 属性可查找封装模块所在程序集的对象。使用 Type..::.Assembly 属性可直接获取封装该类型的程序集。

System.Type 和 ConstructorInfo

下面的示例演示如何列出一个类（此示例中为 String 类）的构造函数。

Visual Basic  复制代码 
' This program lists all the public constructors
            ' of the System.String class.
            Imports System
            Imports System.Reflection
            Class ListMembers
            Public Shared Sub Main()
            Dim t As Type = GetType(String)
            Console.WriteLine("Listing all the public constructors of the {0} type", t)
            ' Constructors.
            Dim ci As ConstructorInfo() = t.GetConstructors((BindingFlags.Public Or BindingFlags.Instance))
            Console.WriteLine("//Constructors")
            PrintMembers(ci)
            End Sub
            Public Shared Sub PrintMembers(ms() As MemberInfo)
            Dim m As MemberInfo
            For Each m In ms
            Console.WriteLine("{0}{1}", "     ", m)
            Next m
            Console.WriteLine()
            End Sub
            End Class
C#  复制代码 
// This program lists all the public constructors
            // of the System.String class.
            using System;
            using System.Reflection;
            class ListMembers {
            public static void Main(String[] args) {
            Type t = typeof(System.String);
            Console.WriteLine ("Listing all the public constructors of the {0} type", t);
            // Constructors.
            ConstructorInfo[] ci = t.GetConstructors(BindingFlags.Public | BindingFlags.Instance);
            Console.WriteLine ("//Constructors");
            PrintMembers (ci);
            }
            public static void PrintMembers(MemberInfo [] ms) {
            foreach (MemberInfo m in ms) {
            Console.WriteLine ("{0}{1}", "     ", m);
            }
            Console.WriteLine();
            }
            }

MemberInfo、MethodInfo、FieldInfo 和 PropertyInfo

使用 MemberInfo、MethodInfo、FieldInfo 或 PropertyInfo 对象获取有关该类型的方法、属性、事件和字段的信息。

下面的示例使用 MemberInfo 列出 System.IO.File 类中的成员数量并使用 System.Type.IsPublic 属性确定该类的可见性。

Visual Basic  复制代码 
Option Explicit
            Option Strict
            Imports System
            Imports System.IO
            Imports System.Reflection
            Imports Microsoft.VisualBasic
            Class Mymemberinfo
            Public Shared Sub Main()
            Console.WriteLine(ControlChars.Cr & "Reflection.MemberInfo")
            ' Gets the Type and MemberInfo.
            Dim MyType As Type = Type.GetType("System.IO.File")
            Dim Mymemberinfoarray As MemberInfo() = MyType.GetMembers()
            ' Gets and displays the DeclaringType method.
            Console.WriteLine(ControlChars.Cr & "There are {0} members in {1}.", Mymemberinfoarray.Length, MyType.FullName)
            Console.WriteLine("{0}.", MyType.FullName)
            If MyType.IsPublic Then
            Console.WriteLine("{0} is public.", MyType.FullName)
            End If
            End Sub
            End Class
C#  复制代码 
using System;
            using System.IO;
            using System.Reflection;
            class Mymemberinfo
            {
            public static void Main(string[] args)
            {
            Console.WriteLine ("\nReflection.MemberInfo");
            // Gets the Type and MemberInfo.
            Type MyType =Type.GetType("System.IO.File");
            MemberInfo[] Mymemberinfoarray = MyType.GetMembers();
            // Gets and displays the DeclaringType method.
            Console.WriteLine("\nThere are {0} members in {1}.",
            Mymemberinfoarray.Length, MyType.FullName);
            Console.WriteLine("{0}.", MyType.FullName);
            if (MyType.IsPublic)
            {
            Console.WriteLine("{0} is public.", MyType.FullName);
            }
            }
            }

下面的示例调查指定成员的类型。它对 MemberInfo 类的一个成员执行反射，然后列出其类型。

Visual Basic  复制代码 
' This code displays information about the GetValue method of FieldInfo.
            Option Explicit
            Option Strict
            Imports System
            Imports System.Reflection
            Class MyMethodInfo
            Public Shared Sub Main()
            Console.WriteLine("Reflection.MethodInfo")
            ' Gets and displays the Type.
            Dim MyType As Type = Type.GetType("System.Reflection.FieldInfo")
            ' Specifies the member for which you want type information.
            Dim Mymethodinfo As MethodInfo = MyType.GetMethod("GetValue")
            Console.WriteLine((MyType.FullName & "." & Mymethodinfo.Name))
            ' Gets and displays the MemberType property.
            Dim Mymembertypes As MemberTypes = Mymethodinfo.MemberType
            If MemberTypes.Constructor = Mymembertypes Then
            Console.WriteLine("MemberType is of type All")
            ElseIf MemberTypes.Custom = Mymembertypes Then
            Console.WriteLine("MemberType is of type Custom")
            ElseIf MemberTypes.Event = Mymembertypes Then
            Console.WriteLine("MemberType is of type Event")
            ElseIf MemberTypes.Field = Mymembertypes Then
            Console.WriteLine("MemberType is of type Field")
            ElseIf MemberTypes.Method = Mymembertypes Then
            Console.WriteLine("MemberType is of type Method")
            ElseIf MemberTypes.Property = Mymembertypes Then
            Console.WriteLine("MemberType is of type Property")
            ElseIf MemberTypes.TypeInfo = Mymembertypes Then
            Console.WriteLine("MemberType is of type TypeInfo")
            End If
            Return
            End Sub
            End Class
C#  复制代码 
// This code displays information about the GetValue method of FieldInfo.
            using System;
            using System.Reflection;
            class MyMethodInfo {
            public static int Main() {
            Console.WriteLine("Reflection.MethodInfo");
            // Gets and displays the Type.
            Type MyType = Type.GetType("System.Reflection.FieldInfo");
            // Specifies the member for which you want type information.
            MethodInfo Mymethodinfo = MyType.GetMethod("GetValue");
            Console.WriteLine(MyType.FullName + "." + Mymethodinfo.Name);
            // Gets and displays the MemberType property.
            MemberTypes Mymembertypes = Mymethodinfo.MemberType;
            if (MemberTypes.Constructor == Mymembertypes) {
            Console.WriteLine("MemberType is of type All");
            }
            else if (MemberTypes.Custom == Mymembertypes) {
            Console.WriteLine("MemberType is of type Custom");
            }
            else if (MemberTypes.Event == Mymembertypes) {
            Console.WriteLine("MemberType is of type Event");
            }
            else if (MemberTypes.Field == Mymembertypes) {
            Console.WriteLine("MemberType is of type Field");
            }
            else if (MemberTypes.Method == Mymembertypes) {
            Console.WriteLine("MemberType is of type Method");
            }
            else if (MemberTypes.Property == Mymembertypes) {
            Console.WriteLine("MemberType is of type Property");
            }
            else if (MemberTypes.TypeInfo == Mymembertypes) {
            Console.WriteLine("MemberType is of type TypeInfo");
            }
            return 0;
            }
            }

下面的示例使用所有的反射 *Info 类以及 BindingFlags 来列出指定类的所有成员（构造函数、字段、属性、事件和方法），并将这些成员划分为静态和实例类别。

Visual Basic  复制代码 
' This program lists all the members of the
            ' System.IO.BufferedStream class.
            Imports System
            Imports System.IO
            Imports System.Reflection
            Imports Microsoft.VisualBasic
            Class ListMembers
            Public Shared Sub Main()
            ' Specifies the class.
            Dim t As Type = GetType(System.IO.BufferedStream)
            Console.WriteLine("Listing all the members (public and non public) of the {0} type", t)
            ' Lists static fields first.
            Dim fi As FieldInfo() = t.GetFields((BindingFlags.Static Or BindingFlags.NonPublic Or BindingFlags.Public))
            Console.WriteLine("// Static Fields")
            PrintMembers(fi)
            ' Static properties.
            Dim pi As PropertyInfo() = t.GetProperties((BindingFlags.Static Or BindingFlags.NonPublic Or BindingFlags.Public))
            Console.WriteLine("// Static Properties")
            PrintMembers(pi)
            ' Static events.
            Dim ei As EventInfo() = t.GetEvents((BindingFlags.Static Or BindingFlags.NonPublic Or BindingFlags.Public))
            Console.WriteLine("// Static Events")
            PrintMembers(ei)
            ' Static methods.
            Dim mi As MethodInfo() = t.GetMethods((BindingFlags.Static Or BindingFlags.NonPublic Or BindingFlags.Public))
            Console.WriteLine("// Static Methods")
            PrintMembers(mi)
            ' Constructors.
            Dim ci As ConstructorInfo() = t.GetConstructors((BindingFlags.Instance Or BindingFlags.NonPublic Or BindingFlags.Public))
            Console.WriteLine("// Constructors")
            PrintMembers(ci)
            ' Instance fields.
            fi = t.GetFields((BindingFlags.Instance Or BindingFlags.NonPublic Or BindingFlags.Public))
            Console.WriteLine("// Instance Fields")
            PrintMembers(fi)
            ' Instance properites.
            pi = t.GetProperties((BindingFlags.Instance Or BindingFlags.NonPublic Or BindingFlags.Public))
            Console.WriteLine("// Instance Properties")
            PrintMembers(pi)
            ' Instance events.
            ei = t.GetEvents((BindingFlags.Instance Or BindingFlags.NonPublic Or BindingFlags.Public))
            Console.WriteLine("// Instance Events")
            PrintMembers(ei)
            ' Instance methods.
            mi = t.GetMethods((BindingFlags.Instance Or BindingFlags.NonPublic Or BindingFlags.Public))
            Console.WriteLine("// Instance Methods")
            PrintMembers(mi)
            Console.WriteLine(ControlChars.CrLf & "Press ENTER to exit.")
            Console.Read()
            End Sub
            Public Shared Sub PrintMembers(ms() As MemberInfo)
            Dim m As MemberInfo
            For Each m In  ms
            Console.WriteLine("{0}{1}", "     ", m)
            Next m
            Console.WriteLine()
            End Sub
            End Class
C#  复制代码 
// This program lists all the members of the
            // System.IO.BufferedStream class.
            using System;
            using System.IO;
            using System.Reflection;
            class ListMembers {
            public static void Main(String[] args) {
            // Specifies the class.
            Type t = typeof (System.IO.BufferedStream);
            Console.WriteLine ("Listing all the members (public and non public) of the {0} type", t);
            // Lists static fields first.
            FieldInfo [] fi = t.GetFields (BindingFlags.Static |
            BindingFlags.NonPublic | BindingFlags.Public);
            Console.WriteLine ("// Static Fields");
            PrintMembers (fi);
            // Static properties.
            PropertyInfo [] pi = t.GetProperties (BindingFlags.Static |
            BindingFlags.NonPublic | BindingFlags.Public);
            Console.WriteLine ("// Static Properties");
            PrintMembers (pi);
            // Static events.
            EventInfo [] ei = t.GetEvents (BindingFlags.Static |
            BindingFlags.NonPublic | BindingFlags.Public);
            Console.WriteLine ("// Static Events");
            PrintMembers (ei);
            // Static methods.
            MethodInfo [] mi = t.GetMethods (BindingFlags.Static |
            BindingFlags.NonPublic | BindingFlags.Public);
            Console.WriteLine ("// Static Methods");
            PrintMembers (mi);
            // Constructors.
            ConstructorInfo [] ci = t.GetConstructors (BindingFlags.Instance |
            BindingFlags.NonPublic | BindingFlags.Public);
            Console.WriteLine ("// Constructors");
            PrintMembers (ci);
            // Instance fields.
            fi = t.GetFields (BindingFlags.Instance | BindingFlags.NonPublic |
            BindingFlags.Public);
            Console.WriteLine ("// Instance Fields");
            PrintMembers (fi);
            // Instance properites.
            pi = t.GetProperties (BindingFlags.Instance | BindingFlags.NonPublic |
            BindingFlags.Public);
            Console.WriteLine ("// Instance Properties");
            PrintMembers (pi);
            // Instance events.
            ei = t.GetEvents (BindingFlags.Instance | BindingFlags.NonPublic |
            BindingFlags.Public);
            Console.WriteLine ("// Instance Events");
            PrintMembers (ei);
            // Instance methods.
            mi = t.GetMethods (BindingFlags.Instance | BindingFlags.NonPublic
            | BindingFlags.Public);
            Console.WriteLine ("// Instance Methods");
            PrintMembers (mi);
            Console.WriteLine ("\r\nPress ENTER to exit.");
            Console.Read();
            }
            public static void PrintMembers (MemberInfo [] ms) {
            foreach (MemberInfo m in ms) {
            Console.WriteLine ("{0}{1}", "     ", m);
            }
            Console.WriteLine();
            }
            }
posted @ 2008-09-26 11:29  花香的蜂  阅读(461)  评论(0)    收藏  举报