DynamicMethod.CreateDelegate Méthode

Définition

Exécute la méthode dynamique et crée un délégué qui peut être utilisé pour l’exécuter.Completes the dynamic method and creates a delegate that can be used to execute it.

Surcharges

CreateDelegate(Type)

Exécute la méthode dynamique et crée un délégué qui peut être utilisé pour l’exécuter.Completes the dynamic method and creates a delegate that can be used to execute it.

CreateDelegate(Type, Object)

Exécute la méthode dynamique et crée un délégué qui peut être utilisé pour l’exécuter, en spécifiant le type de délégué et un objet auquel le délégué est lié.Completes the dynamic method and creates a delegate that can be used to execute it, specifying the delegate type and an object the delegate is bound to.

CreateDelegate(Type)

Exécute la méthode dynamique et crée un délégué qui peut être utilisé pour l’exécuter.Completes the dynamic method and creates a delegate that can be used to execute it.

public:
 Delegate ^ CreateDelegate(Type ^ delegateType);
[System.Runtime.InteropServices.ComVisible(true)]
public Delegate CreateDelegate (Type delegateType);
member this.CreateDelegate : Type -> Delegate
Public Function CreateDelegate (delegateType As Type) As Delegate

Paramètres

delegateType
Type

Type de délégué dont la signature correspond à celle de la méthode dynamique.A delegate type whose signature matches that of the dynamic method.

Retours

Délégué du type spécifié, qui peut être utilisé pour exécuter la méthode dynamique.A delegate of the specified type, which can be used to execute the dynamic method.

Attributs

Exceptions

La méthode dynamique ne possède aucun corps de méthode.The dynamic method has no method body.

delegateType possède un nombre erroné de paramètres ou des types de paramètre incorrects.delegateType has the wrong number of parameters or the wrong parameter types.

Exemples

L’exemple de code suivant crée une méthode dynamique qui accepte deux paramètres.The following code example creates a dynamic method that takes two parameters. L’exemple émet un corps de fonction simple qui imprime le premier paramètre de la console, et l’exemple utilise le deuxième paramètre comme valeur de retour de la méthode.The example emits a simple function body that prints the first parameter to the console, and the example uses the second parameter as the return value of the method. L’exemple termine la méthode en créant un délégué, appelle le délégué avec des paramètres différents, puis appelle la méthode dynamique à l’aide de la méthode Invoke.The example completes the method by creating a delegate, invokes the delegate with different parameters, and finally invokes the dynamic method using the Invoke method.

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

public ref class Test
{   
};

// Declare a delegate that will be used to execute the completed
// dynamic method.
delegate int HelloInvoker(String^ msg, int ret);

int main()
{
    // Create an array that specifies the types of the parameters
    // of the dynamic method. This method has a string parameter
    // and an int parameter.
    array<Type^>^ helloArgs = {String::typeid, int::typeid};

    // Create a dynamic method with the name "Hello", a return type
    // of int, and two parameters whose types are specified by the
    // array helloArgs. Create the method in the module that
    // defines the Test class.
    DynamicMethod^ hello = gcnew DynamicMethod("Hello", 
        int::typeid,
        helloArgs,
        Test::typeid->Module);

    // Create an array that specifies the parameter types of the
    // overload of Console.WriteLine to be used in Hello.
    array<Type^>^ writeStringArgs = {String::typeid};
    // Get the overload of Console.WriteLine that has one
    // String parameter.
    MethodInfo^ writeString =
        Console::typeid->GetMethod("WriteLine", writeStringArgs);

    // Get an ILGenerator and emit a body for the dynamic method.
    ILGenerator^ ilgen = hello->GetILGenerator();
    // Load the first argument, which is a string, onto the stack.
    ilgen->Emit(OpCodes::Ldarg_0);
    // Call the overload of Console.WriteLine that prints a string.
    ilgen->EmitCall(OpCodes::Call, writeString, nullptr);
    // The Hello method returns the value of the second argument;
    // to do this, load the onto the stack and return.
    ilgen->Emit(OpCodes::Ldarg_1);
    ilgen->Emit(OpCodes::Ret);

    // Create a delegate that represents the dynamic method. This
    // action completes the method, and any further attempts to
    // change the method will cause an exception.
    HelloInvoker^ helloDelegate =
        (HelloInvoker^) hello->CreateDelegate(HelloInvoker::typeid);

    // Use the delegate to execute the dynamic method. Save and
    // print the return value.
    int returnValue = helloDelegate("\r\nHello, World!", 42);
    Console::WriteLine("helloDelegate(\"Hello, World!\", 42) returned {0}",
        returnValue);

    // Do it again, with different arguments.
    returnValue = helloDelegate("\r\nHi, Mom!", 5280);
    Console::WriteLine("helloDelegate(\"Hi, Mom!\", 5280) returned {0}",
        returnValue);

    // Create an array of arguments to use with the Invoke method.
    array<Object^>^ delegateArgs = {"\r\nHello, World!", 42};
    // Invoke the dynamic method using the arguments. This is much
    // slower than using the delegate, because you must create an
    // array to contain the arguments, and ValueType arguments
    // must be boxed.
    Object^ returnValueObject = hello->Invoke(nullptr, delegateArgs);
    Console::WriteLine("hello.Invoke returned {0}", returnValueObject);
}
using System;
using System.Reflection;
using System.Reflection.Emit;
using Microsoft.VisualBasic;

public class Test
{
    // Declare a delegate that will be used to execute the completed
    // dynamic method. 
    private delegate int HelloInvoker(string msg, int ret);

    public static void Main()
    {
        // Create an array that specifies the types of the parameters
        // of the dynamic method. This method has a string parameter
        // and an int parameter.
        Type[] helloArgs = {typeof(string), typeof(int)};

        // Create a dynamic method with the name "Hello", a return type
        // of int, and two parameters whose types are specified by the
        // array helloArgs. Create the method in the module that
        // defines the Test class.
        DynamicMethod hello = new DynamicMethod("Hello", 
            typeof(int), 
            helloArgs, 
            typeof(Test).Module);

        // Create an array that specifies the parameter types of the
        // overload of Console.WriteLine to be used in Hello.
        Type[] writeStringArgs = {typeof(string)};
        // Get the overload of Console.WriteLine that has one
        // String parameter.
        MethodInfo writeString = 
            typeof(Console).GetMethod("WriteLine", writeStringArgs);

        // Get an ILGenerator and emit a body for the dynamic method.
        ILGenerator il = hello.GetILGenerator();
        // Load the first argument, which is a string, onto the stack.
        il.Emit(OpCodes.Ldarg_0);
        // Call the overload of Console.WriteLine that prints a string.
        il.EmitCall(OpCodes.Call, writeString, null);
        // The Hello method returns the value of the second argument;
        // to do this, load the onto the stack and return.
        il.Emit(OpCodes.Ldarg_1);
        il.Emit(OpCodes.Ret);

        // Create a delegate that represents the dynamic method. This
        // action completes the method, and any further attempts to
        // change the method will cause an exception.
        HelloInvoker hi = 
            (HelloInvoker) hello.CreateDelegate(typeof(HelloInvoker));

        // Use the delegate to execute the dynamic method. Save and
        // print the return value.
        int retval = hi("\r\nHello, World!", 42);
        Console.WriteLine("Executing delegate hi(\"Hello, World!\", 42) returned {0}",
            retval);

        // Do it again, with different arguments.
        retval = hi("\r\nHi, Mom!", 5280);
        Console.WriteLine("Executing delegate hi(\"Hi, Mom!\", 5280) returned {0}",
            retval);
        
        // Create an array of arguments to use with the Invoke method.
        object[] invokeArgs = {"\r\nHello, World!", 42};
        // Invoke the dynamic method using the arguments. This is much
        // slower than using the delegate, because you must create an
        // array to contain the arguments, and ValueType arguments
        // must be boxed.
        object objRet = hello.Invoke(null, invokeArgs);
        Console.WriteLine("hello.Invoke returned {0}", objRet);
    }
}
Imports System.Reflection
Imports System.Reflection.Emit

Public Class Test
    ' Declare a delegate that will be used to execute the completed
    ' dynamic method. 
    Private Delegate Function HelloInvoker(ByVal msg As String, _
        ByVal ret As Integer) As Integer

    Public Shared Sub Main()
        ' Create an array that specifies the types of the parameters
        ' of the dynamic method. This method has a String parameter
        ' and an Integer parameter.
        Dim helloArgs() As Type = {GetType(String), GetType(Integer)}

        ' Create a dynamic method with the name "Hello", a return type
        ' of Integer, and two parameters whose types are specified by
        ' the array helloArgs. Create the method in the module that
        ' defines the Test class.
        Dim hello As New DynamicMethod("Hello", _
            GetType(Integer), _
            helloArgs, _
            GetType(Test).Module)

        ' Create an array that specifies the parameter types of the
        ' overload of Console.WriteLine to be used in Hello.
        Dim writeStringArgs() As Type = {GetType(String)}
        ' Get the overload of Console.WriteLine that has one
        ' String parameter.
        Dim writeString As MethodInfo = GetType(Console). _
            GetMethod("WriteLine", writeStringArgs) 

        ' Get an ILGenerator and emit a body for the dynamic method.
        Dim il As ILGenerator = hello.GetILGenerator()
        ' Load the first argument, which is a string, onto the stack.
        il.Emit(OpCodes.Ldarg_0)
        ' Call the overload of Console.WriteLine that prints a string.
        il.EmitCall(OpCodes.Call, writeString, Nothing)
        ' The Hello method returns the value of the second argument;
        ' to do this, load the onto the stack and return.
        il.Emit(OpCodes.Ldarg_1)
        il.Emit(OpCodes.Ret)

        ' Create a delegate that represents the dynamic method. This
        ' action completes the method, and any further attempts to
        ' change the method will cause an exception.
    Dim hi As HelloInvoker = _
            hello.CreateDelegate(GetType(HelloInvoker))

        ' Use the delegate to execute the dynamic method. Save and
        ' print the return value.
        Dim retval As Integer = hi(vbCrLf & "Hello, World!", 42)
        Console.WriteLine("Executing delegate hi(""Hello, World!"", 42) returned " _
            & retval)

        ' Do it again, with different arguments.
        retval = hi(vbCrLf & "Hi, Mom!", 5280)
        Console.WriteLine("Executing delegate hi(""Hi, Mom!"", 5280) returned " _
            & retval)

        ' Create an array of arguments to use with the Invoke method.
        Dim invokeArgs() As Object = {vbCrLf & "Hello, World!", 42}
        ' Invoke the dynamic method using the arguments. This is much
        ' slower than using the delegate, because you must create an
        ' array to contain the arguments, and ValueType arguments
        ' must be boxed. Note that this overload of Invoke is 
        ' inherited from MethodBase, and simply calls the more 
        ' complete overload of Invoke.
        Dim objRet As Object = hello.Invoke(Nothing, invokeArgs)
        Console.WriteLine("hello.Invoke returned " & objRet)
    End Sub
End Class

' This code example produces the following output:
'
'Hello, World!
'Executing delegate hi("Hello, World!", 42) returned 42
'
'Hi, Mom!
'Executing delegate hi("Hi, Mom!", 5280) returned 5280
'
'Hello, World!
'hello.Invoke returned 42
'

Remarques

L’appel de la méthode CreateDelegate ou de la méthode Invoke termine la méthode dynamique.Calling the CreateDelegate method or the Invoke method completes the dynamic method. Toute tentative supplémentaire de modification de la méthode dynamique, telle que la modification des définitions de paramètres ou l’émission d’un plus grand langage MSIL (Microsoft Intermediate Language), est ignorée. aucune exception n’est levée.Any further attempt to alter the dynamic method, such as modifying parameter definitions or emitting more Microsoft intermediate language (MSIL), is ignored; no exception is thrown.

Pour créer un corps de méthode pour une méthode dynamique lorsque vous avez votre propre générateur MSIL, appelez la méthode GetDynamicILInfo pour obtenir un objet DynamicILInfo.To create a method body for a dynamic method when you have your own MSIL generator, call the GetDynamicILInfo method to obtain a DynamicILInfo object. Si vous n’avez pas votre propre générateur MSIL, appelez la méthode GetILGenerator pour obtenir un objet ILGenerator qui peut être utilisé pour générer le corps de la méthode.If you do not have your own MSIL generator, call the GetILGenerator method to obtain an ILGenerator object that can be used to generate the method body.

Voir aussi

CreateDelegate(Type, Object)

Exécute la méthode dynamique et crée un délégué qui peut être utilisé pour l’exécuter, en spécifiant le type de délégué et un objet auquel le délégué est lié.Completes the dynamic method and creates a delegate that can be used to execute it, specifying the delegate type and an object the delegate is bound to.

public:
 Delegate ^ CreateDelegate(Type ^ delegateType, System::Object ^ target);
[System.Runtime.InteropServices.ComVisible(true)]
public Delegate CreateDelegate (Type delegateType, object target);
member this.CreateDelegate : Type * obj -> Delegate
Public Function CreateDelegate (delegateType As Type, target As Object) As Delegate

Paramètres

delegateType
Type

Type de délégué dont la signature correspond à celle de la méthode dynamique, moins le premier paramètre.A delegate type whose signature matches that of the dynamic method, minus the first parameter.

target
Object

Objet auquel le délégué est lié.An object the delegate is bound to. Doit être du même type que le premier paramètre de la méthode dynamique.Must be of the same type as the first parameter of the dynamic method.

Retours

Délégué du type spécifié, qui peut être utilisé pour exécuter la méthode dynamique avec l’objet cible spécifié.A delegate of the specified type, which can be used to execute the dynamic method with the specified target object.

Attributs

Exceptions

La méthode dynamique ne possède aucun corps de méthode.The dynamic method has no method body.

target n’est pas du même type que le premier paramètre de la méthode dynamique et ne peut pas être assigné à ce type.target is not the same type as the first parameter of the dynamic method, and is not assignable to that type.

- ou --or- delegateType possède un nombre erroné de paramètres ou des types de paramètre incorrects.delegateType has the wrong number of parameters or the wrong parameter types.

Exemples

L’exemple de code suivant crée un délégué qui lie une DynamicMethod à une instance d’un type, afin que la méthode agisse sur la même instance chaque fois qu’elle est appelée.The following code example creates delegate that binds a DynamicMethod to an instance of a type, so that the method acts on the same instance each time it is invoked.

L’exemple de code définit une classe nommée Example avec un champ privé, une classe nommée DerivedFromExample qui dérive de la première classe, un type délégué nommé UseLikeStatic qui retourne Int32 et a des paramètres de type Example et Int32, et un type délégué nommé UseLikeInstance qui retourne Int32 et qui a un paramètre de type Int32.The code example defines a class named Example with a private field, a class named DerivedFromExample that derives from the first class, a delegate type named UseLikeStatic that returns Int32 and has parameters of type Example and Int32, and a delegate type named UseLikeInstance that returns Int32 and has one parameter of type Int32.

L’exemple de code crée ensuite une DynamicMethod qui modifie le champ privé d’une instance de Example et retourne la valeur précédente.The example code then creates a DynamicMethod that changes the private field of an instance of Example and returns the previous value.

Notes

En général, la modification des champs internes des classes n’est pas une bonne pratique de codage orientée objet.In general, changing the internal fields of classes is not good object-oriented coding practice.

L’exemple de code crée une instance de Example, puis crée deux délégués.The example code creates an instance of Example and then creates two delegates. Le premier est de type UseLikeStatic, qui a les mêmes paramètres que la méthode dynamique.The first is of type UseLikeStatic, which has the same parameters as the dynamic method. Le deuxième est de type UseLikeInstance, qui ne possède pas le premier paramètre (de type Example).The second is of type UseLikeInstance, which lacks the first parameter (of type Example). Ce délégué est créé à l’aide de la surcharge de méthode CreateDelegate(Type, Object) ; le deuxième paramètre de cette surcharge de méthode est une instance de Example, dans le cas présent, l’instance qui vient d’être créée, qui est liée au délégué nouvellement créé.This delegate is created using the CreateDelegate(Type, Object) method overload; the second parameter of that method overload is an instance of Example, in this case the instance just created, which is bound to the newly created delegate. Chaque fois que ce délégué est appelé, la méthode dynamique agit sur l’instance liée de Example.Whenever that delegate is invoked, the dynamic method acts on the bound instance of Example.

Notes

Il s’agit d’un exemple des règles assouplies pour la liaison déléguée introduite dans le .NET Framework 2.0.NET Framework 2.0, ainsi que de nouvelles surcharges de la méthode Delegate.CreateDelegate.This is an example of the relaxed rules for delegate binding introduced in the .NET Framework 2.0.NET Framework 2.0, along with new overloads of the Delegate.CreateDelegate method. Pour plus d'informations, consultez la classe Delegate.For more information, see the Delegate class.

Le délégué UseLikeStatic est appelé, en passant l’instance de Example liée au délégué UseLikeInstance.The UseLikeStatic delegate is invoked, passing in the instance of Example that is bound to the UseLikeInstance delegate. Ensuite, le délégué UseLikeInstance est appelé, afin que les deux délégués agissent sur la même instance de Example.Then the UseLikeInstance delegate is invoked, so that both delegates act on the same instance of Example. Les modifications apportées aux valeurs du champ interne sont affichées après chaque appel.The changes in the values of the internal field are displayed after each call. Enfin, un délégué UseLikeInstance est lié à une instance de DerivedFromExample, et les appels de délégué sont répétés.Finally, a UseLikeInstance delegate is bound to an instance of DerivedFromExample, and the delegate calls are repeated.

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

// These classes are for demonstration purposes.
//
public class Example
{
    private int id = 0;
    public Example(int id)
    {
        this.id = id;
    }
    public int ID { get { return id; }}
}

public class DerivedFromExample : Example
{
    public DerivedFromExample(int id) : base(id) {} 
}

// Two delegates are declared: UseLikeInstance treats the dynamic
// method as if it were an instance method, and UseLikeStatic
// treats the dynamic method in the ordinary fashion.
// 
public delegate int UseLikeInstance(int newID);
public delegate int UseLikeStatic(Example ex, int newID);

public class Demo
{
    public static void Main()
    {
        // This dynamic method changes the private id field. It has
        // no name; it returns the old id value (return type int);
        // it takes two parameters, an instance of Example and 
        // an int that is the new value of id; and it is declared 
        // with Example as the owner type, so it can access all 
        // members, public and private.
        //
        DynamicMethod changeID = new DynamicMethod(
            "",
            typeof(int),
            new Type[] { typeof(Example), typeof(int) },
            typeof(Example)
        );

        // Get a FieldInfo for the private field 'id'.
        FieldInfo fid = typeof(Example).GetField(
            "id",
            BindingFlags.NonPublic | BindingFlags.Instance
        );
    
        ILGenerator ilg = changeID.GetILGenerator();

        // Push the current value of the id field onto the 
        // evaluation stack. It's an instance field, so load the
        // instance of Example before accessing the field.
        ilg.Emit(OpCodes.Ldarg_0);
        ilg.Emit(OpCodes.Ldfld, fid);

        // Load the instance of Example again, load the new value 
        // of id, and store the new field value. 
        ilg.Emit(OpCodes.Ldarg_0);
        ilg.Emit(OpCodes.Ldarg_1);
        ilg.Emit(OpCodes.Stfld, fid);

        // The original value of the id field is now the only 
        // thing on the stack, so return from the call.
        ilg.Emit(OpCodes.Ret);

        // Create a delegate that uses changeID in the ordinary
        // way, as a static method that takes an instance of
        // Example and an int.
        //
        UseLikeStatic uls = 
            (UseLikeStatic) changeID.CreateDelegate(
                typeof(UseLikeStatic)
            );

        // Create an instance of Example with an id of 42.
        //
        Example ex = new Example(42);

        // Create a delegate that is bound to the instance of 
        // of Example. This is possible because the first 
        // parameter of changeID is of type Example. The 
        // delegate has all the parameters of changeID except
        // the first.
        UseLikeInstance uli = 
            (UseLikeInstance) changeID.CreateDelegate(
                typeof(UseLikeInstance),
                ex
            );

        // First, change the value of id by calling changeID as
        // a static method, passing in the instance of Example.
        //
        Console.WriteLine(
            "Change the value of id; previous value: {0}",
            uls(ex, 1492)
        );

        // Change the value of id again using the delegate bound
        // to the instance of Example.
        //
        Console.WriteLine(
            "Change the value of id; previous value: {0}",
            uli(2700)
        );

        Console.WriteLine("Final value of id: {0}", ex.ID);

        // Now repeat the process with a class that derives
        // from Example.
        //
        DerivedFromExample dfex = new DerivedFromExample(71);

        uli = (UseLikeInstance) changeID.CreateDelegate(
                typeof(UseLikeInstance),
                dfex
            );

        Console.WriteLine(
            "Change the value of id; previous value: {0}",
            uls(dfex, 73)
        );
        Console.WriteLine(
            "Change the value of id; previous value: {0}",
            uli(79)
        );
        Console.WriteLine("Final value of id: {0}", dfex.ID);
    }
}

/* This code example produces the following output:

Change the value of id; previous value: 42
Change the value of id; previous value: 1492
Final value of id: 2700
Change the value of id; previous value: 71
Change the value of id; previous value: 73
Final value of id: 79
 */
Imports System.Reflection
Imports System.Reflection.Emit

' These classes are for demonstration purposes.
'
Public Class Example
    Private _id As Integer = 0
    
    Public Sub New(ByVal newId As Integer) 
        _id = newId    
    End Sub
    
    Public ReadOnly Property ID() As Integer 
        Get
            Return _id
        End Get
    End Property 
End Class

Public Class DerivedFromExample
    Inherits Example
    
    Public Sub New(ByVal newId As Integer) 
        MyBase.New(newId)
    End Sub
End Class
 
' Two delegates are declared: UseLikeInstance treats the dynamic
' method as if it were an instance method, and UseLikeStatic
' treats the dynamic method in the ordinary fashion.
' 
Public Delegate Function UseLikeInstance(ByVal newID As Integer) _
    As Integer 
Public Delegate Function UseLikeStatic(ByVal ex As Example, _
    ByVal newID As Integer) As Integer 

Public Class Demo
    
    Public Shared Sub Main() 
        ' This dynamic method changes the private _id field. It 
        ' has no name; it returns the old _id value (return type 
        ' Integer); it takes two parameters, an instance of Example 
        ' and an Integer that is the new value of _id; and it is 
        ' declared with Example as the owner type, so it can 
        ' access all members, public and private.
        '
        Dim changeID As New DynamicMethod( _
            "", _
            GetType(Integer), _
            New Type() {GetType(Example), GetType(Integer)}, _
            GetType(Example) _
        )
        
        ' Get a FieldInfo for the private field '_id'.
        Dim fid As FieldInfo = GetType(Example).GetField( _
            "_id", _
            BindingFlags.NonPublic Or BindingFlags.Instance _
        )
        
        Dim ilg As ILGenerator = changeID.GetILGenerator()
        
        ' Push the current value of the id field onto the 
        ' evaluation stack. It's an instance field, so load the
        ' instance of Example before accessing the field.
        ilg.Emit(OpCodes.Ldarg_0)
        ilg.Emit(OpCodes.Ldfld, fid)
        
        ' Load the instance of Example again, load the new value 
        ' of id, and store the new field value. 
        ilg.Emit(OpCodes.Ldarg_0)
        ilg.Emit(OpCodes.Ldarg_1)
        ilg.Emit(OpCodes.Stfld, fid)
        
        ' The original value of the id field is now the only 
        ' thing on the stack, so return from the call.
        ilg.Emit(OpCodes.Ret)
        
        
        ' Create a delegate that uses changeID in the ordinary
        ' way, as a static method that takes an instance of
        ' Example and an Integer.
        '
        Dim uls As UseLikeStatic = CType( _
            changeID.CreateDelegate(GetType(UseLikeStatic)), _
            UseLikeStatic _
        )
        
        ' Create an instance of Example with an id of 42.
        '
        Dim ex As New Example(42)
        
        ' Create a delegate that is bound to the instance of 
        ' of Example. This is possible because the first 
        ' parameter of changeID is of type Example. The 
        ' delegate has all the parameters of changeID except
        ' the first.
        Dim uli As UseLikeInstance = CType( _
            changeID.CreateDelegate( _
                GetType(UseLikeInstance), _
                ex), _
            UseLikeInstance _
        )
        
        ' First, change the value of _id by calling changeID as
        ' a static method, passing in the instance of Example.
        '
        Console.WriteLine( _
            "Change the value of _id; previous value: {0}", _
            uls(ex, 1492) _
        )
        
        ' Change the value of _id again using the delegate 
        ' bound to the instance of Example.
        '
        Console.WriteLine( _
            "Change the value of _id; previous value: {0}", _
            uli(2700) _
        )
        
        Console.WriteLine("Final value of _id: {0}", ex.ID)
    

        ' Now repeat the process with a class that derives
        ' from Example.
        '
        Dim dfex As New DerivedFromExample(71)

        uli = CType( _
            changeID.CreateDelegate( _
                GetType(UseLikeInstance), _
                dfex), _
            UseLikeInstance _
        )

        Console.WriteLine( _
            "Change the value of _id; previous value: {0}", _
            uls(dfex, 73) _
        )
        Console.WriteLine( _
            "Change the value of _id; previous value: {0}", _
            uli(79) _
        )
        Console.WriteLine("Final value of _id: {0}", dfex.ID)

    End Sub
End Class

' This code example produces the following output:
'
'Change the value of _id; previous value: 42
'Change the value of _id; previous value: 1492
'Final value of _id: 2700
'Change the value of _id; previous value: 71
'Change the value of _id; previous value: 73
'Final value of _id: 79' 

Remarques

Cette surcharge de méthode crée un délégué lié à un objet particulier.This method overload creates a delegate bound to a particular object. Un délégué de ce type est dit fermé sur son premier argument.Such a delegate is said to be closed over its first argument. Bien que la méthode soit statique, elle agit comme s’il s’agissait d’une méthode d’instance ; l’instance est target.Although the method is static, it acts as if it were an instance method; the instance is target.

Cette surcharge de méthode exige target être du même type que le premier paramètre de la méthode dynamique, ou être assignée à ce type (par exemple, une classe dérivée).This method overload requires target to be of the same type as the first parameter of the dynamic method, or to be assignable to that type (for example, a derived class). La signature de delegateType a tous les paramètres de la méthode dynamique, à l’exception de la première.The signature of delegateType has all the parameters of the dynamic method except the first. Par exemple, si la méthode dynamique a les paramètres String, Int32et Byte, delegateType a les paramètres Int32 et Byte; target est de type String.For example, if the dynamic method has the parameters String, Int32, and Byte, then delegateType has the parameters Int32 and Byte; target is of type String.

L’appel de la méthode CreateDelegate ou de la méthode Invoke termine la méthode dynamique.Calling the CreateDelegate method or the Invoke method completes the dynamic method. Toute tentative supplémentaire de modification de la méthode dynamique, telle que la modification des définitions de paramètres ou l’émission d’un plus grand langage MSIL (Microsoft Intermediate Language), est ignorée. aucune exception n’est levée.Any further attempt to alter the dynamic method, such as modifying parameter definitions or emitting more Microsoft intermediate language (MSIL), is ignored; no exception is thrown.

Pour créer un corps de méthode pour une méthode dynamique lorsque vous avez votre propre générateur MSIL, appelez la méthode GetDynamicILInfo pour obtenir un objet DynamicILInfo.To create a method body for a dynamic method when you have your own MSIL generator, call the GetDynamicILInfo method to obtain a DynamicILInfo object. Si vous n’avez pas votre propre générateur MSIL, appelez la méthode GetILGenerator pour obtenir un objet ILGenerator qui peut être utilisé pour générer le corps de la méthode.If you do not have your own MSIL generator, call the GetILGenerator method to obtain an ILGenerator object that can be used to generate the method body.

S’applique à