Anzeigen von Typinformationen

Artikel
08/10/2011

Die System.Type-Klasse ist für die Reflektion von zentraler Bedeutung. Auf Anforderung der Reflektion erstellt Common Language Runtime den Type für einen geladenen Typ. Sie können die Methoden, Felder, Eigenschaften und geschachtelten Klassen dieses Type-Objekts verwenden, um sämtliche Informationen über diesen Typ zu erhalten.

Mit Assembly.GetType oder Assembly.GetTypes können Sie Type-Objekte nicht geladener Assemblys abrufen, indem Sie den Namen des gewünschten Typs bzw. der gewünschten Typen übergeben. Mit Type.GetType können Sie Type-Objekte einer bereits geladenen Assembly abrufen. Mit Module.GetType und Module.GetTypes können Sie Type-Modulobjekte abrufen.

Hinweis
Zusätzliche Informationen zum Überprüfen und Bearbeiten von generischen Typen und Methoden finden Sie unter Reflektion und generische Typen und Gewusst wie: Untersuchen und Instanziieren von generischen Typen mit Reflektion.

Das folgende Beispiel zeigt die Syntax, die erforderlich ist, um das Assembly-Objekt und -Modul für eine Assembly abzurufen.

' Gets the mscorlib assembly in which the object is defined.
Dim a As Assembly = GetType(Object).Module.Assembly

// Gets the mscorlib assembly in which the object is defined.
Assembly a = typeof(object).Module.Assembly;

// Gets the mscorlib assembly in which the object is defined.
Assembly^ a = Object::typeid->Module->Assembly;

Im folgenden Beispiel werden die Namen von Type-Objekten einer geladenen Assembly ausgegeben.

' Loads an assembly using its file name.
Dim a As Assembly = Assembly.LoadFrom("MyExe.exe")
' Gets the type names from the assembly.
Dim types2() As Type = a.GetTypes()
For Each t As Type In types2
    Console.WriteLine(t.FullName)
Next t

// 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);
}

// Loads an assembly using its file name.
Assembly^ a = Assembly::LoadFrom("MyExe.exe");
// Gets the type names from the assembly.
array<Type^>^ types2 = a->GetTypes();
for each (Type^ t in types2)
{
    Console::WriteLine(t->FullName);
}

Sobald Sie einen Type erhalten haben, gibt es viele Möglichkeiten, Informationen über die Member dieses Typs zu erhalten. Um Informationen über alle Member eines Typs zu erhalten, können Sie z. B. die Type.GetMembers-Methode aufrufen. Diese ruft wiederum ein Array von MemberInfo-Objekten ab, die alle Member des aktuellen Typs beschreiben.

Sie können auch Methoden der Type-Klasse verwenden, um Informationen über einen oder mehrere Konstruktoren, Methoden, Ereignisse, Felder oder Eigenschaften zu erhalten, die Sie mit Namen angeben. Type.GetConstructor kapselt beispielsweise einen bestimmten Konstruktor der aktuellen Klasse.

Wenn Sie über einen Type verfügen, können Sie die Type.Module-Eigenschaft verwenden, um ein Objekt abzurufen, das das Modul mit dem Typ kapselt. Verwenden Sie die Module.Assembly-Eigenschaft zum Suchen eines Objekts, das die Assembly mit dem Modul kapselt. Sie können die Assembly, die den Typ kapselt, mit der Type.Assembly-Eigenschaft direkt abrufen.

System.Type und ConstructorInfo

Im folgenden Beispiel werden die Konstruktoren einer Klasse (in diesem Fall der String-Klasse) aufgelistet.

' 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

// This program lists all the public constructors
// of the System.String class.
using System;
using System.Reflection;

class ListMembers
{
    public static void Main()
    {
        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();
    }
}

// This program lists all the public constructors
// of the System.String class.
using namespace System;
using namespace System::Reflection;

class ListMembers
{
public:
    static void Main()
    {
        Type^ t = System::String::typeid;
        Console::WriteLine ("Listing all the public constructors of the {0} type", t);
        // Constructors.
        array<ConstructorInfo^>^ ci = t->GetConstructors(BindingFlags::Public | BindingFlags::Instance);
        Console::WriteLine ("//Constructors");
        PrintMembers(ci);
    }

    static void PrintMembers(array<MemberInfo^>^ ms)
    {
        for each (MemberInfo^ m in ms)
        {
            Console::WriteLine ("{0}{1}", "     ", m);
        }
        Console::WriteLine();
    }
};

int main()
{
    ListMembers::Main();
}

MemberInfo, MethodInfo, FieldInfo und PropertyInfo

Informationen über die Methoden, Eigenschaften, Ereignisse und Felder eines Typs können Sie mit den Objekten MemberInfo, MethodInfo, FieldInfo und PropertyInfo abrufen.

Im folgenden Beispiel wird MemberInfo verwendet, um die Anzahl der Member der System.IO.File-Klasse aufzulisten. Die System.Type.IsPublic-Eigenschaft dient zum Bestimmen der Sichtbarkeit der Klasse.

Imports System
Imports System.IO
Imports System.Reflection

Class Mymemberinfo
    Public Shared Sub Main()
        Console.WriteLine ("\nReflection.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("\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)
        End If
    End Sub
End Class

using System;
using System.IO;
using System.Reflection;

class Mymemberinfo
{
    public static void Main()
    {
        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);
        }
    }
}

using namespace System;
using namespace System::IO;
using namespace System::Reflection;

public ref class Mymemberinfo
{
public:
    static void Main()
    {
        Console::WriteLine ("\nReflection.MemberInfo");
        // Gets the Type and MemberInfo.
        Type^ MyType = Type::GetType("System.IO.File");
        array<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);
        }
    }
};

int main()
{
    Mymemberinfo::Main();
}

Im folgenden Beispiel wird der Typ eines angegebenen Members untersucht. Für einen Member der MemberInfo-Klasse wird Reflektion durchgeführt. Anschließend wird dessen Typ angezeigt.

' This code displays information about the GetValue method of FieldInfo.
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

// 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;
    }
}

// This code displays information about the GetValue method of FieldInfo.
using namespace System;
using namespace System::Reflection;

public ref 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;
    }
};

int main()
{
    MyMethodInfo::Main();
}

Im folgenden Beispiel werden die *Info-Klassen der Reflektion zusammen mit BindingFlags verwendet, um alle Member (Konstruktoren, Felder, Eigenschaften, Ereignisse und Methoden) der angegebenen Klasse aufzulisten. Die Member werden in statische und Instanzkategorien unterteilt.

' This program lists all the members of the
' System.IO.BufferedStream class.
Imports System
Imports System.IO
Imports System.Reflection

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

// 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()
    {
        // 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();
    }
}

// This program lists all the members of the
// System.IO.BufferedStream class.
using namespace System;
using namespace System::IO;
using namespace System::Reflection;

public ref class ListMembers
{
public:
    static void Main()
    {
        // Specifies the class.
        Type^ t = System::IO::BufferedStream::typeid;
        Console::WriteLine("Listing all the members (public and non public) of the {0} type", t);

        // Lists static fields first.
        array<FieldInfo^>^ fi = t->GetFields(BindingFlags::Static |
            BindingFlags::NonPublic | BindingFlags::Public);
        Console::WriteLine("// Static Fields");
        PrintMembers(fi);

        // Static properties.
        array<PropertyInfo^>^ pi = t->GetProperties(BindingFlags::Static |
            BindingFlags::NonPublic | BindingFlags::Public);
        Console::WriteLine("// Static Properties");
        PrintMembers(pi);

        // Static events.
        array<EventInfo^>^ ei = t->GetEvents(BindingFlags::Static |
            BindingFlags::NonPublic | BindingFlags::Public);
        Console::WriteLine("// Static Events");
        PrintMembers(ei);

        // Static methods.
        array<MethodInfo^>^ mi = t->GetMethods (BindingFlags::Static |
            BindingFlags::NonPublic | BindingFlags::Public);
        Console::WriteLine("// Static Methods");
        PrintMembers(mi);

        // Constructors.
        array<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();
    }

    static void PrintMembers(array<MemberInfo^>^ ms)
    {
        for each (MemberInfo^ m in ms)
        {
            Console::WriteLine ("{0}{1}", "     ", m);
        }
        Console::WriteLine();
    }
};

int main()
{
    ListMembers::Main();
}