DynamicMethod 类

定义

public ref class DynamicMethod sealed : System::Reflection::MethodInfo

public sealed class DynamicMethod : System.Reflection.MethodInfo

[System.Runtime.InteropServices.ComVisible(true)]
public sealed class DynamicMethod : System.Reflection.MethodInfo

type DynamicMethod = class
    inherit MethodInfo

[<System.Runtime.InteropServices.ComVisible(true)>]
type DynamicMethod = class
    inherit MethodInfo

Public NotInheritable Class DynamicMethod
Inherits MethodInfo

继承

Object

MemberInfo

MethodBase

MethodInfo

DynamicMethod

属性

ComVisibleAttribute

示例

下面的代码示例创建一个采用两个参数的动态方法。 该示例发出一个简单的函数体，该函数体将第一个参数打印到控制台，该示例使用第二个参数作为 方法的返回值。 该示例通过创建委托完成方法，使用不同的参数调用委托，最后使用 Invoke 方法调用动态方法。

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

// Declare a delegate type that can be used to execute the completed
// dynamic method. 
private delegate int HelloDelegate(String^ msg, int ret);

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

    // 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 String class.
    DynamicMethod^ hello = gcnew DynamicMethod("Hello", 
        int::typeid, 
        helloArgs, 
        String::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,
    // using a stream size larger than the IL that will be
    // emitted.
    ILGenerator^ il = hello->GetILGenerator(256);
    // 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, nullptr);
    // 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);

    // Add parameter information to the dynamic method. (This is not
    // necessary, but can be useful for debugging.) For each parameter,
    // identified by position, supply the parameter attributes and a 
    // parameter name.
    hello->DefineParameter(1, ParameterAttributes::In, "message");
    hello->DefineParameter(2, ParameterAttributes::In, "valueToReturn");

    // Create a delegate that represents the dynamic method. This
    // action completes the method. Any further attempts to
    // change the method are ignored.
    HelloDelegate^ hi = 
        (HelloDelegate^) hello->CreateDelegate(HelloDelegate::typeid);

    // Use the delegate to execute the dynamic method.
    Console::WriteLine("\r\nUse the delegate to execute the dynamic method:");
    int retval = hi("\r\nHello, World!", 42);
    Console::WriteLine("Invoking delegate hi(\"Hello, World!\", 42) returned: " + retval);

    // Execute it again, with different arguments.
    retval = hi("\r\nHi, Mom!", 5280);
    Console::WriteLine("Invoking delegate hi(\"Hi, Mom!\", 5280) returned: " + retval);

    Console::WriteLine("\r\nUse the Invoke method to execute the dynamic method:");
    // Create an array of arguments to use with the Invoke method.
    array<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 value-type arguments
    // must be boxed.
    Object^ objRet = hello->Invoke(nullptr, BindingFlags::ExactBinding, nullptr, invokeArgs, gcnew CultureInfo("en-us"));
    Console::WriteLine("hello.Invoke returned: " + objRet);

    Console::WriteLine("\r\n ----- Display information about the dynamic method -----");
    // Display MethodAttributes for the dynamic method, set when 
    // the dynamic method was created.
    Console::WriteLine("\r\nMethod Attributes: {0}", hello->Attributes);

    // Display the calling convention of the dynamic method, set when the 
    // dynamic method was created.
    Console::WriteLine("\r\nCalling convention: {0}", hello->CallingConvention);

    // Display the declaring type, which is always null for dynamic
    // methods.
    if (hello->DeclaringType == nullptr)
    {
        Console::WriteLine("\r\nDeclaringType is always null for dynamic methods.");
    }
    else
    {
        Console::WriteLine("DeclaringType: {0}", hello->DeclaringType);
    }

    // Display the default value for InitLocals.
    if (hello->InitLocals)
    {
        Console::Write("\r\nThis method contains verifiable code.");
    }
    else
    {
        Console::Write("\r\nThis method contains unverifiable code.");
    }
    Console::WriteLine(" (InitLocals = {0})", hello->InitLocals);

    // Display the module specified when the dynamic method was created.
    Console::WriteLine("\r\nModule: {0}", hello->Module);

    // Display the name specified when the dynamic method was created.
    // Note that the name can be blank.
    Console::WriteLine("\r\nName: {0}", hello->Name);

    // For dynamic methods, the reflected type is always null.
    if (hello->ReflectedType == nullptr)
    {
        Console::WriteLine("\r\nReflectedType is null.");
    }
    else
    {
        Console::WriteLine("\r\nReflectedType: {0}", hello->ReflectedType);
    }

    if (hello->ReturnParameter == nullptr)
    {
        Console::WriteLine("\r\nMethod has no return parameter.");
    }
    else
    {
        Console::WriteLine("\r\nReturn parameter: {0}", hello->ReturnParameter);
    }

    // If the method has no return type, ReturnType is System.Void.
    Console::WriteLine("\r\nReturn type: {0}", hello->ReturnType);

    // ReturnTypeCustomAttributes returns an ICustomeAttributeProvider
    // that can be used to enumerate the custom attributes of the
    // return value. At present, there is no way to set such custom
    // attributes, so the list is empty.
    if (hello->ReturnType == Void::typeid)
    {
        Console::WriteLine("The method has no return type.");
    }
    else
    {
        ICustomAttributeProvider^ caProvider = hello->ReturnTypeCustomAttributes;
        array<Object^>^ returnAttributes = caProvider->GetCustomAttributes(true);
        if (returnAttributes->Length == 0)
        {
            Console::WriteLine("\r\nThe return type has no custom attributes.");
        }
        else
        {
            Console::WriteLine("\r\nThe return type has the following custom attributes:");
            for each (Object^ attr in returnAttributes)
            {
                Console::WriteLine("\t{0}", attr->ToString());
            }
        }
    }

    Console::WriteLine("\r\nToString: {0}", hello->ToString());

    // Display parameter information.
    array<ParameterInfo^>^ parameters = hello->GetParameters();
    Console::WriteLine("\r\nParameters: name, type, ParameterAttributes");
    for each (ParameterInfo^ p in parameters)
    {
        Console::WriteLine("\t{0}, {1}, {2}", 
            p->Name, p->ParameterType, p->Attributes);
    }
}

/* This code example produces the following output:

Use the delegate to execute the dynamic method:

Hello, World!
Invoking delegate hi("Hello, World!", 42) returned: 42

Hi, Mom!
Invoking delegate hi("Hi, Mom!", 5280) returned: 5280

Use the Invoke method to execute the dynamic method:

Hello, World!
hello.Invoke returned: 42

 ----- Display information about the dynamic method -----

Method Attributes: PrivateScope, Public, Static

Calling convention: Standard

DeclaringType is always null for dynamic methods.

This method contains verifiable code. (InitLocals = True)

Module: CommonLanguageRuntimeLibrary

Name: Hello

ReflectedType is null.

Method has no return parameter.

Return type: System.Int32

The return type has no custom attributes.

ToString: Int32 Hello(System.String, Int32)

Parameters: name, type, ParameterAttributes
        message, System.String, In
        valueToReturn, System.Int32, In
 */

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

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

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

        // 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 String class.
        DynamicMethod hello = new DynamicMethod("Hello",
            typeof(int),
            helloArgs,
            typeof(string).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,
        // using a stream size larger than the IL that will be
        // emitted.
        ILGenerator il = hello.GetILGenerator(256);
        // 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);

        // Add parameter information to the dynamic method. (This is not
        // necessary, but can be useful for debugging.) For each parameter,
        // identified by position, supply the parameter attributes and a
        // parameter name.
        hello.DefineParameter(1, ParameterAttributes.In, "message");
        hello.DefineParameter(2, ParameterAttributes.In, "valueToReturn");

        // Create a delegate that represents the dynamic method. This
        // action completes the method. Any further attempts to
        // change the method are ignored.
        HelloDelegate hi =
            (HelloDelegate) hello.CreateDelegate(typeof(HelloDelegate));

        // Use the delegate to execute the dynamic method.
        Console.WriteLine("\r\nUse the delegate to execute the dynamic method:");
        int retval = hi("\r\nHello, World!", 42);
        Console.WriteLine("Invoking delegate hi(\"Hello, World!\", 42) returned: " + retval);

        // Execute it again, with different arguments.
        retval = hi("\r\nHi, Mom!", 5280);
        Console.WriteLine("Invoking delegate hi(\"Hi, Mom!\", 5280) returned: " + retval);

        Console.WriteLine("\r\nUse the Invoke method to execute the dynamic method:");
        // 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 value-type arguments
        // must be boxed.
        object objRet = hello.Invoke(null, BindingFlags.ExactBinding, null, invokeArgs, new CultureInfo("en-us"));
        Console.WriteLine("hello.Invoke returned: " + objRet);

        Console.WriteLine("\r\n ----- Display information about the dynamic method -----");
        // Display MethodAttributes for the dynamic method, set when
        // the dynamic method was created.
        Console.WriteLine("\r\nMethod Attributes: {0}", hello.Attributes);

        // Display the calling convention of the dynamic method, set when the
        // dynamic method was created.
        Console.WriteLine("\r\nCalling convention: {0}", hello.CallingConvention);

        // Display the declaring type, which is always null for dynamic
        // methods.
        if (hello.DeclaringType == null)
        {
            Console.WriteLine("\r\nDeclaringType is always null for dynamic methods.");
        }
        else
        {
            Console.WriteLine("DeclaringType: {0}", hello.DeclaringType);
        }

        // Display the default value for InitLocals.
        if (hello.InitLocals)
        {
            Console.Write("\r\nThis method contains verifiable code.");
        }
        else
        {
            Console.Write("\r\nThis method contains unverifiable code.");
        }
        Console.WriteLine(" (InitLocals = {0})", hello.InitLocals);

        // Display the module specified when the dynamic method was created.
        Console.WriteLine("\r\nModule: {0}", hello.Module);

        // Display the name specified when the dynamic method was created.
        // Note that the name can be blank.
        Console.WriteLine("\r\nName: {0}", hello.Name);

        // For dynamic methods, the reflected type is always null.
        if (hello.ReflectedType == null)
        {
            Console.WriteLine("\r\nReflectedType is null.");
        }
        else
        {
            Console.WriteLine("\r\nReflectedType: {0}", hello.ReflectedType);
        }

        if (hello.ReturnParameter == null)
        {
            Console.WriteLine("\r\nMethod has no return parameter.");
        }
        else
        {
            Console.WriteLine("\r\nReturn parameter: {0}", hello.ReturnParameter);
        }

        // If the method has no return type, ReturnType is System.Void.
        Console.WriteLine("\r\nReturn type: {0}", hello.ReturnType);

        // ReturnTypeCustomAttributes returns an ICustomeAttributeProvider
        // that can be used to enumerate the custom attributes of the
        // return value. At present, there is no way to set such custom
        // attributes, so the list is empty.
        if (hello.ReturnType == typeof(void))
        {
            Console.WriteLine("The method has no return type.");
        }
        else
        {
            ICustomAttributeProvider caProvider = hello.ReturnTypeCustomAttributes;
            object[] returnAttributes = caProvider.GetCustomAttributes(true);
            if (returnAttributes.Length == 0)
            {
                Console.WriteLine("\r\nThe return type has no custom attributes.");
            }
            else
            {
                Console.WriteLine("\r\nThe return type has the following custom attributes:");
                foreach( object attr in returnAttributes )
                {
                    Console.WriteLine("\t{0}", attr.ToString());
                }
            }
        }

        Console.WriteLine("\r\nToString: {0}", hello.ToString());

        // Display parameter information.
        ParameterInfo[] parameters = hello.GetParameters();
        Console.WriteLine("\r\nParameters: name, type, ParameterAttributes");
        foreach( ParameterInfo p in parameters )
        {
            Console.WriteLine("\t{0}, {1}, {2}",
                p.Name, p.ParameterType, p.Attributes);
        }
    }
}

/* This code example produces the following output:

Use the delegate to execute the dynamic method:

Hello, World!
Invoking delegate hi("Hello, World!", 42) returned: 42

Hi, Mom!
Invoking delegate hi("Hi, Mom!", 5280) returned: 5280

Use the Invoke method to execute the dynamic method:

Hello, World!
hello.Invoke returned: 42

 ----- Display information about the dynamic method -----

Method Attributes: PrivateScope, Public, Static

Calling convention: Standard

DeclaringType is always null for dynamic methods.

This method contains verifiable code. (InitLocals = True)

Module: CommonLanguageRuntimeLibrary

Name: Hello

ReflectedType is null.

Method has no return parameter.

Return type: System.Int32

The return type has no custom attributes.

ToString: Int32 Hello(System.String, Int32)

Parameters: name, type, ParameterAttributes
        message, System.String, In
        valueToReturn, System.Int32, In
 */

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

Public Class Test
    ' Declare a delegate type that can be used to execute the completed
    ' dynamic method. 
    Private Delegate Function HelloDelegate(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 dynamic 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 String class.
        Dim hello As New DynamicMethod("Hello", _
            GetType(Integer), _
            helloArgs, _
            GetType(String).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,
        ' using a stream size larger than the IL that will be
        ' emitted.
        Dim il As ILGenerator = hello.GetILGenerator(256)
        ' 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)

        ' Add parameter information to the dynamic method. (This is not
        ' necessary, but can be useful for debugging.) For each parameter,
        ' identified by position, supply the parameter attributes and a 
        ' parameter name.
        hello.DefineParameter(1, ParameterAttributes.In, "message")
        hello.DefineParameter(2, ParameterAttributes.In, "valueToReturn")

        ' Create a delegate that represents the dynamic method. This
        ' action completes the method. Any further attempts to
        ' change the method are ignored.
    Dim hi As HelloDelegate = _
            CType(hello.CreateDelegate(GetType(HelloDelegate)), HelloDelegate)

        ' Use the delegate to execute the dynamic method.
        Console.WriteLine(vbCrLf & "Use the delegate to execute the dynamic method:")
        Dim retval As Integer = hi(vbCrLf & "Hello, World!", 42)
        Console.WriteLine("Invoking delegate hi(""Hello, World!"", 42) returned: " _
            & retval & ".")

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

        Console.WriteLine(vbCrLf & "Use the Invoke method to execute the dynamic method:")
        ' 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 value-type arguments
        ' must be boxed.
        Dim objRet As Object = hello.Invoke(Nothing, _
            BindingFlags.ExactBinding, Nothing, invokeArgs, _
            New CultureInfo("en-us"))
        Console.WriteLine("hello.Invoke returned: {0}", objRet)

        Console.WriteLine(vbCrLf & _
            " ----- Display information about the dynamic method -----")
        ' Display MethodAttributes for the dynamic method, set when 
        ' the dynamic method was created.
        Console.WriteLine(vbCrLf & "Method Attributes: {0}", _
            hello.Attributes)

        ' Display the calling convention of the dynamic method, set when the 
        ' dynamic method was created.
        Console.WriteLine(vbCrLf & "Calling convention: {0}", _ 
            hello.CallingConvention)

        ' Display the declaring type, which is always Nothing for dynamic
        ' methods.
        If hello.DeclaringType Is Nothing Then
            Console.WriteLine(vbCrLf & "DeclaringType is always Nothing for dynamic methods.")
        Else
            Console.WriteLine("DeclaringType: {0}", hello.DeclaringType)
        End If

        ' Display the default value for InitLocals.
        If hello.InitLocals Then
            Console.Write(vbCrLf & "This method contains verifiable code.")
        Else
            Console.Write(vbCrLf & "This method contains unverifiable code.")
        End If
        Console.WriteLine(" (InitLocals = {0})", hello.InitLocals)

        ' Display the module specified when the dynamic method was created.
        Console.WriteLine(vbCrLf & "Module: {0}", hello.Module)

        ' Display the name specified when the dynamic method was created.
        ' Note that the name can be blank.
        Console.WriteLine(vbCrLf & "Name: {0}", hello.Name)

        ' For dynamic methods, the reflected type is always Nothing.
        If hello.ReflectedType Is Nothing Then
            Console.WriteLine(vbCrLf & "ReflectedType is Nothing.")
        Else
            Console.WriteLine(vbCrLf & "ReflectedType: {0}", _
                hello.ReflectedType)
        End If

        If hello.ReturnParameter Is Nothing Then
            Console.WriteLine(vbCrLf & "Method has no return parameter.")
        Else
            Console.WriteLine(vbCrLf & "Return parameter: {0}", _
                hello.ReturnParameter)
        End If

        ' If the method has no return type, ReturnType is System.Void.
        Console.WriteLine(vbCrLf & "Return type: {0}", hello.ReturnType)           

        ' ReturnTypeCustomAttributes returns an ICustomeAttributeProvider
        ' that can be used to enumerate the custom attributes of the
        ' return value. At present, there is no way to set such custom
        ' attributes, so the list is empty.
        If hello.ReturnType Is GetType(System.Void) Then
            Console.WriteLine("The method has no return type.")
        Else
            Dim caProvider As ICustomAttributeProvider = _
                hello.ReturnTypeCustomAttributes
            Dim returnAttributes() As Object = _
                caProvider.GetCustomAttributes(True)
            If returnAttributes.Length = 0 Then
                Console.WriteLine(vbCrLf _
                    & "The return type has no custom attributes.")
            Else
                Console.WriteLine(vbCrLf _
                    & "The return type has the following custom attributes:")
                For Each attr As Object In returnAttributes
                    Console.WriteLine(vbTab & attr.ToString())
                Next attr
            End If
        End If

        Console.WriteLine(vbCrLf & "ToString: " & hello.ToString())

        ' Display parameter information.
        Dim parameters() As ParameterInfo = hello.GetParameters()
        Console.WriteLine(vbCrLf & "Parameters: name, type, ParameterAttributes")
        For Each p As ParameterInfo In parameters
            Console.WriteLine(vbTab & "{0}, {1}, {2}", _ 
                p.Name, p.ParameterType, p.Attributes)
        Next p
    End Sub
End Class

' This code example produces the following output:
'
'Use the delegate to execute the dynamic method:
'
'Hello, World!
'Invoking delegate hi("Hello, World!", 42) returned: 42.
'
'Hi, Mom!
'Invoking delegate hi("Hi, Mom!", 5280) returned: 5280.
'
'Use the Invoke method to execute the dynamic method:
'
'Hello, World!
'hello.Invoke returned: 42
'
' ----- Display information about the dynamic method -----
'
'Method Attributes: PrivateScope, Public, Static
'
'Calling convention: Standard
'
'DeclaringType is always Nothing for dynamic methods.
'
'This method contains verifiable code. (InitLocals = True)
'
'Module: CommonLanguageRuntimeLibrary
'
'Name: Hello
'
'ReflectedType is Nothing.
'
'Method has no return parameter.
'
'Return type: System.Int32
'
'The return type has no custom attributes.
'
'ToString: Int32 Hello(System.String, Int32)
'
'Parameters: name, type, ParameterAttributes
'        message, System.String, In
'        valueToReturn, System.Int32, In

注解

有关此 API 的详细信息，请参阅 DynamicMethod 的补充 API 备注。

构造函数

属性

方法

显式接口实现

扩展方法

适用于

另请参阅

• 如何：定义和执行动态方法
• 反射发出中的安全问题
• 演练：在部分信任应用场景中发出代码