Visualizzare le informazioni sul tipo

Articolo
04/01/2024

La classe System.Type è fondamentale per la reflection. Common Language Runtime crea per Type un tipo caricato quando la reflection lo richiede. È possibile usare metodi, campi, proprietà e classi annidate di un Type oggetto per scoprire tutto su tale tipo.

Utilizzare Assembly.GetType o Assembly.GetTypes per ottenere Type oggetti dagli assembly che non sono stati caricati, passando il nome del tipo o dei tipi desiderati. Utilizzare Type.GetType per ottenere gli Type oggetti da un assembly già caricato. Usare Module.GetType e Module.GetTypes per ottenere oggetti modulo Type .

Nota

Se si vuole esaminare e modificare tipi e metodi generici, vedere le altre informazioni disponibili in Reflection e tipi generici e Procedura: Esaminare e creare istanze di tipi generici tramite reflection.

L'esempio seguente illustra la sintassi necessaria per ottenere il modulo e l'oggetto Assembly per un assembly.

// Gets the mscorlib assembly in which the object is defined.
Assembly^ a = Object::typeid->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.
Dim a As Assembly = GetType(Object).Module.Assembly

Nell'esempio seguente viene illustrato il recupero Type di oggetti da un assembly caricato.

// 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);
}

// 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.
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

Dopo aver ottenuto un Typeoggetto , è possibile individuare informazioni sui membri di tale tipo in molti modi. Ad esempio, per ottenere informazioni su tutti i membri del tipo è possibile chiamare il metodo Type.GetMembers che ottiene una matrice di oggetti MemberInfo ognuno dei quali descrive un membro del tipo corrente.

È anche possibile utilizzare metodi nella Type classe per recuperare informazioni su uno o più costruttori, metodi, eventi, campi o proprietà specificati in base al nome. Ad esempio, Type.GetConstructor incapsula uno costruttore specifico della classe corrente.

Se si dispone di un Typeoggetto , è possibile utilizzare la Type.Module proprietà per ottenere un oggetto che incapsula il modulo contenente tale tipo. Usare la proprietà Module.Assembly per individuare un oggetto che incapsula l'assembly contenente il modulo. Per ottenere direttamente l'assembly che incapsula il tipo, usare la proprietà Type.Assembly.

System.Type e ConstructorInfo

L'esempio seguente illustra come elencare i costruttori di una classe, nel caso specifico la classe String.

// 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();
}

// 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.

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

MemberInfo, MethodInfo, FieldInfo e PropertyInfo

Per ottenere informazioni su metodi, proprietà, eventi e campi del tipo, usare gli oggetti MemberInfo, MethodInfo, FieldInfo o PropertyInfo.

Nell'esempio seguente viene MemberInfo usato per elencare il numero di membri nella System.IO.File classe e viene utilizzata la IsPublic proprietà per determinare la visibilità della classe .

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();
}

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);
        }
    }
}

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

L'esempio seguente analizza il tipo del membro specificato. Esegue la reflection su un membro della MemberInfo classe e ne elenca il tipo.

// 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();
}

// 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.
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

Nell'esempio seguente vengono utilizzate tutte le classi Reflection *Info insieme BindingFlags a per elencare tutti i membri (costruttori, campi, proprietà, eventi e metodi) della classe specificata, dividendo i membri in categorie statiche e di istanza.

// 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 properties.
        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();
}

// 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 properties.
        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.
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 properties.
        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

Condividi tramite

Visualizzare le informazioni sul tipo

System.Type e ConstructorInfo

MemberInfo, MethodInfo, FieldInfo e PropertyInfo

Risorse aggiuntive