AppDomain.TypeResolve-Ereignis

Artikel
08/20/2007

Tritt ein, wenn die Auflösung eines Typs fehlschlägt.

Namespace: System
Assembly: mscorlib (in mscorlib.dll)

Syntax

'Declaration
Public Event TypeResolve As ResolveEventHandler
'Usage
Dim instance As AppDomain
Dim handler As ResolveEventHandler

AddHandler instance.TypeResolve, handler

public event ResolveEventHandler TypeResolve

public:
virtual event ResolveEventHandler^ TypeResolve {
    void add (ResolveEventHandler^ value) sealed;
    void remove (ResolveEventHandler^ value) sealed;
}

/** @event */
public final void add_TypeResolve (ResolveEventHandler value)

/** @event */
public final void remove_TypeResolve (ResolveEventHandler value)

JScript unterstützt die Verwendung von Ereignissen, aber nicht die Deklaration von neuen Ereignissen.

Hinweise

Das TypeResolve-Ereignis tritt ein, wenn die Common Language Runtime die Assembly zum Erstellen des angeforderten Typs nicht bestimmen kann. Dies kann der Fall sein, wenn der Typ in einer dynamischen Assembly definiert ist oder wenn der Typ nicht in einer dynamischen Assembly definiert ist, aber die Common Language Runtime die Assembly mit der Definition des Typs nicht kennt. Der letztgenannte Fall kann eintreten, wenn Type.GetType mit einem Typnamen aufgerufen wird, der nicht mit dem Assemblynamen qualifiziert ist.

Der ResolveEventHandler für dieses Ereignis kann versuchen, den Typ zu finden und zu erstellen.

Das TypeResolve-Ereignis tritt hingegen nicht ein, wenn die Common Language Runtime davon ausgeht, dass ein Typ in bestimmten Assemblys nicht gefunden werden kann. Das Ereignis tritt z. B. nicht ein, wenn der Typ nicht in einer statischen Assembly gefunden werden kann, da die Common Language Runtime davon ausgeht, dass Typen statischen Assemblys nicht dynamisch hinzugefügt werden können.

Zum Registrieren eines Ereignishandlers für dieses Ereignis müssen Sie über die erforderlichen Berechtigungen verfügen. Andernfalls wird eine SecurityException ausgelöst.

Weitere Informationen zum Behandeln von Ereignissen finden Sie unter Behandeln von Ereignissen.

Beispiel

Im folgenden Beispiel wird das TypeResolve-Ereignis veranschaulicht.

Damit dieses Codebeispiel ausgeführt werden kann, müssen Sie den vollqualifizierten Assemblynamen bereitstellen. Informationen über das Abrufen des voll gekennzeichneten Assemblynamens finden Sie unter Assemblynamen.

Option Strict On
Option Explicit On

Imports System
Imports System.Reflection
Imports System.Reflection.Emit

Module Test

    ' For this code example, the following information needs to be
    ' available to both Main and the HandleTypeResolve event
    ' handler:
    Private ab As AssemblyBuilder
    Private moduleName As String

    Sub Main() 
    
        Dim currDom As AppDomain = AppDomain.CurrentDomain

        ' Create a dynamic assembly with one module, to be saved to 
        ' disk (AssemblyBuilderAccess.Save).
        ' 
        Dim aName As AssemblyName = new AssemblyName()
        aName.Name = "Transient"
        moduleName = aName.Name + ".dll"
        ab = currDom.DefineDynamicAssembly(aName, _
            AssemblyBuilderAccess.Save)
        Dim mb As ModuleBuilder = _
            ab.DefineDynamicModule(aName.Name, moduleName)

        ' The dynamic assembly has just one dummy type, to demonstrate
        ' type resolution.
        Dim tb As TypeBuilder = mb.DefineType("Example")
        tb.CreateType()


        ' First, try to load the type without saving the dynamic 
        ' assembly and without hooking up the TypeResolve event. The
        ' type cannot be loaded.
        Try
            Dim temp As Type = Type.GetType("Example", true)
            Console.WriteLine("Loaded type {0}.", temp)
        Catch ex As TypeLoadException
            Console.WriteLine("Loader could not resolve the type.")
        End Try

        ' Hook up the TypeResolve event.
        '      
        AddHandler currDom.TypeResolve, AddressOf HandleTypeResolve

        ' Now try to load the type again. The TypeResolve event is 
        ' raised, the dynamic assembly is saved, and the dummy type is
        ' loaded successfully. Display it to the console, and create
        ' an instance.
        Dim t As Type = Type.GetType("Example", true)
        Console.WriteLine("Loaded type ""{0}"".", t)
        Dim o As Object = Activator.CreateInstance(t)
    End Sub

    Private Function HandleTypeResolve(ByVal sender As Object, _
        ByVal e As ResolveEventArgs) As [Assembly]
    
        Console.WriteLine("TypeResolve event handler.")

        ' Save the dynamic assembly, and then load it using its
        ' display name. Return the loaded assembly.
        '
        ab.Save(moduleName)
        Return [Assembly].Load(ab.FullName) 
    End Function
End Module

' This code example produces the following output:
'
'Loader could not resolve the type.
'TypeResolve event handler.
'Loaded type "Example".
'

using System;
using System.Reflection;
using System.Reflection.Emit;

class Test 
{
    // For this code example, the following information needs to be
    // available to both Main and the HandleTypeResolve event
    // handler:
    private static AssemblyBuilder ab;
    private static string moduleName;

    public static void Main() 
    {
        AppDomain currDom = AppDomain.CurrentDomain;

        // Create a dynamic assembly with one module, to be saved to 
        // disk (AssemblyBuilderAccess.Save).
        // 
        AssemblyName aName = new AssemblyName();
        aName.Name = "Transient";
        moduleName = aName.Name + ".dll";
        ab = currDom.DefineDynamicAssembly(aName,
            AssemblyBuilderAccess.Save);
        ModuleBuilder mb = ab.DefineDynamicModule(aName.Name, moduleName);

        // The dynamic assembly has just one dummy type, to demonstrate
        // type resolution.
        TypeBuilder tb = mb.DefineType("Example");
        tb.CreateType();


        // First, try to load the type without saving the dynamic 
        // assembly and without hooking up the TypeResolve event. The
        // type cannot be loaded.
        try
        {
            Type temp = Type.GetType("Example", true);
            Console.WriteLine("Loaded type {0}.", temp);
        }
        catch (TypeLoadException)
        {
            Console.WriteLine("Loader could not resolve the type.");
        }

        // Hook up the TypeResolve event.
        //      
        currDom.TypeResolve += 
            new ResolveEventHandler(HandleTypeResolve);

        // Now try to load the type again. The TypeResolve event is 
        // raised, the dynamic assembly is saved, and the dummy type is
        // loaded successfully. Display it to the console, and create
        // an instance.
        Type t = Type.GetType("Example", true);
        Console.WriteLine("Loaded type \"{0}\".", t);
        Object o = Activator.CreateInstance(t);
    }

    static Assembly HandleTypeResolve(object sender, ResolveEventArgs args) 
    {
        Console.WriteLine("TypeResolve event handler.");

        // Save the dynamic assembly, and then load it using its
        // display name. Return the loaded assembly.
        //
        ab.Save(moduleName);
        return Assembly.Load(ab.FullName); 
    }
}

/* This code example produces the following output:

Loader could not resolve the type.
TypeResolve event handler.
Loaded type "Example".
 */

#using <System.dll>
#using <System.Windows.Forms.dll>
#using <System.Drawing.dll>

using namespace System;
using namespace System::Reflection;
using namespace System::Reflection::Emit;

ref class Test
{
private:
    static Assembly^ HandleTypeResolve(Object^ sender, ResolveEventArgs^ args) 
    {
        Console::WriteLine("TypeResolve event handler.");

        // Save the dynamic assembly, and then load it using its
        // display name. Return the loaded assembly.
        //
        ab->Save(moduleName);
        return Assembly::Load(ab->FullName); 
    }

    // For this code example, the following information needs to be
    // available to both Demo and the HandleTypeResolve event
    // handler:
    static AssemblyBuilder^ ab;
    static String^ moduleName;

public:
    static void Demo() 
    {
        AppDomain^ currDom = AppDomain::CurrentDomain;

        // Create a dynamic assembly with one module, to be saved to 
        // disk (AssemblyBuilderAccess::Save).
        // 
        AssemblyName^ aName = gcnew AssemblyName();
        aName->Name = "Transient";
        moduleName = aName->Name + ".dll";
        ab = currDom->DefineDynamicAssembly(aName,
            AssemblyBuilderAccess::Save);
        ModuleBuilder^ mb = ab->DefineDynamicModule(aName->Name, moduleName);

        // The dynamic assembly has just one dummy type, to demonstrate
        // type resolution.
        TypeBuilder^ tb = mb->DefineType("Example");
        tb->CreateType();


        // First, try to load the type without saving the dynamic 
        // assembly and without hooking up the TypeResolve event. The
        // type cannot be loaded.
        try
        {
            Type^ temp = Type::GetType("Example", true);
            Console::WriteLine("Loaded type {0}.", temp);
        }
        catch (TypeLoadException^)
        {
            Console::WriteLine("Loader could not resolve the type.");
        }

        // Hook up the TypeResolve event.
        //      
        currDom->TypeResolve += 
            gcnew ResolveEventHandler(HandleTypeResolve);

        // Now try to load the type again. The TypeResolve event is 
        // raised, the dynamic assembly is saved, and the dummy type is
        // loaded successfully. Display it to the console, and create
        // an instance.
        Type^ t = Type::GetType("Example", true);
        Console::WriteLine("Loaded type \"{0}\".", t);
        Object^ o = Activator::CreateInstance(t);
    }
};

void main()
{
    Test::Demo();
}

/* This code example produces the following output:

Loader could not resolve the type.
TypeResolve event handler.
Loaded type "Example".
 */

.NET Framework-Sicherheit

SecurityPermission zum Hinzufügen eines Ereignishandlers für dieses Ereignis. Zugeordnete Enumeration: SecurityPermissionFlag.ControlAppDomain.

Plattformen

Windows 98, Windows 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile für Pocket PC, Windows Mobile für Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

.NET Framework unterstützt nicht alle Versionen sämtlicher Plattformen. Eine Liste der unterstützten Versionen finden Sie unter Systemanforderungen.

Freigeben über

AppDomain.TypeResolve-Ereignis

Syntax

Hinweise

Beispiel

.NET Framework-Sicherheit

Plattformen

Versionsinformationen

.NET Framework

Siehe auch

Referenz

Zusätzliche Ressourcen