MethodRental.SwapMethodBody(Type, Int32, IntPtr, Int32, Int32) Metoda

Odwołanie

Definicja

Przestrzeń nazw:: System.Reflection.Emit

Zestaw:: mscorlib.dll

Ważne

Niektóre informacje odnoszą się do produktu w wersji wstępnej, który może zostać znacząco zmodyfikowany przed wydaniem. Firma Microsoft nie udziela żadnych gwarancji, jawnych lub domniemanych, w odniesieniu do informacji podanych w tym miejscu.

Zamienia treść metody.

public:
 static void SwapMethodBody(Type ^ cls, int methodtoken, IntPtr rgIL, int methodSize, int flags);

public static void SwapMethodBody (Type cls, int methodtoken, IntPtr rgIL, int methodSize, int flags);

static member SwapMethodBody : Type * int * nativeint * int * int -> unit

Public Shared Sub SwapMethodBody (cls As Type, methodtoken As Integer, rgIL As IntPtr, methodSize As Integer, flags As Integer)

Parametry

cls: Type

Klasa zawierająca metodę .

methodtoken: Int32

Token metody .

rgIL: IntPtr
nativeint

Wskaźnik do metody . Powinno to obejmować nagłówek metody.

methodSize: Int32

Rozmiar nowej treści metody w bajtach.

flags: Int32

Flagi kontrolujące zamianę. Zobacz definicje stałych.

Wyjątki

ArgumentNullException

cls to null.

NotSupportedException

Typ cls nie został ukończony.

ArgumentException

methodSize jest mniejszy niż jeden lub większy niż 4128767 (szesnastkowy 3effff).

Przykłady

W poniższym przykładzie pokazano, jak zamienić treść metody dla nowej treści. Pokazano również, jak uzyskać token metody dla istniejącej metody i jak skonstruować obiekt blob bajtów reprezentujący kod języka Microsoft Intermediate Language (MSIL) do przekazania do SwapMethodBody.

using namespace System;
using namespace System::Reflection;
using namespace System::Reflection::Emit;
using namespace System::Runtime::InteropServices;

// First make a method that returns 0.
// Then swap the method body with a body that returns 1.
int main()
{
   // Construct a dynamic assembly
   Guid g = Guid::NewGuid();
   AssemblyName^ asmname = gcnew AssemblyName;
   asmname->Name = String::Concat( "tempfile", g );
   AssemblyBuilder^ asmbuild = System::Threading::Thread::GetDomain()->DefineDynamicAssembly( asmname, AssemblyBuilderAccess::Run );

   // Add a dynamic module that contains one type that has one method that
   // has no arguments.
   ModuleBuilder^ modbuild = asmbuild->DefineDynamicModule( "test" );
   TypeBuilder^ tb = modbuild->DefineType( "name of the Type" );
   array<Type^>^temp2;
   MethodBuilder^ somemethod = tb->DefineMethod( "My method Name", static_cast<MethodAttributes>(MethodAttributes::Public | MethodAttributes::Static), int::typeid, temp2 );

   // Define the body of the method to return 0.
   ILGenerator^ ilg = somemethod->GetILGenerator();
   ilg->Emit( OpCodes::Ldc_I4_0 );
   ilg->Emit( OpCodes::Ret );

   // Complete the type and verify that it returns 0.
   Type^ tbBaked = tb->CreateType();
   array<Object^>^temp0;
   int res1 = safe_cast<Int32>(tbBaked->GetMethod( "My method Name" )->Invoke( nullptr, temp0 ));
   if ( res1 != 0 )
   {
      Console::WriteLine( "Err_001a, should have returned 0" );
   }
   else
   {
      Console::WriteLine( "Original method returned 0" );
   }

   // Define a new method body that will return a 1 instead.

   // code size
   // ldc_i4_1
   // ret
   array<Byte>^methodBytes = {0x03,0x30,0x0A,0x00,0x02,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x17,0x2a};

   // Get the token for the method whose body you are replacing.
   MethodToken somemethodToken = somemethod->GetToken();

   // Get the pointer to the method body.
   GCHandle hmem = GCHandle::Alloc( (Object^)methodBytes, GCHandleType::Pinned );
   IntPtr addr = hmem.AddrOfPinnedObject();
   int cbSize = methodBytes->Length;

   // Swap the old method body with the new body.
   MethodRental::SwapMethodBody( tbBaked, somemethodToken.Token, addr, cbSize, MethodRental::JitImmediate );

   // Verify that the modified method returns 1.
   array<Object^>^temp1;
   int res2 = safe_cast<Int32>(tbBaked->GetMethod( "My method Name" )->Invoke( nullptr, temp1 ));
   if ( res2 != 1 )
   {
      Console::WriteLine( "Err_001b, should have returned 1" );
   }
   else
   {
      Console::WriteLine( "Swapped method body returned 1" );
   }
}

using System;
using System.Reflection;
using System.Reflection.Emit;
using System.Runtime.InteropServices;

class SwapMethodBodySample
{
    // First make a method that returns 0.
    // Then swap the method body with a body that returns 1.
    public static void Main(string [] args)
    {
    // Construct a dynamic assembly
    Guid g = Guid.NewGuid();
    AssemblyName asmname = new AssemblyName();
    asmname.Name = "tempfile" + g;
    AssemblyBuilder asmbuild = System.Threading.Thread.GetDomain().
        DefineDynamicAssembly(asmname, AssemblyBuilderAccess.Run);

    // Add a dynamic module that contains one type that has one method that
    // has no arguments.
    ModuleBuilder modbuild = asmbuild.DefineDynamicModule( "test");
        TypeBuilder tb = modbuild.DefineType( "name of the Type" );
        MethodBuilder somemethod = tb.DefineMethod
            ("My method Name",
             MethodAttributes.Public | MethodAttributes.Static,
             typeof(int),
             new Type[]{} );
    // Define the body of the method to return 0.
        ILGenerator ilg = somemethod.GetILGenerator();
    ilg.Emit(OpCodes.Ldc_I4_0);
    ilg.Emit(OpCodes.Ret);

    // Complete the type and verify that it returns 0.
    Type tbBaked = tb.CreateType();
    int res1 = (int)tbBaked.GetMethod("My method Name").Invoke( null, new Object[]{} );
    if ( res1 != 0 ) {
        Console.WriteLine( "Err_001a, should have returned 0" );
    } else {
        Console.WriteLine("Original method returned 0");
    }

    // Define a new method body that will return a 1 instead.
    Byte[] methodBytes = {
        0x03,
        0x30,
        0x0A,
        0x00,
        0x02,                // code size
        0x00,
        0x00,
        0x00,
        0x00,
        0x00,
        0x00,
        0x00,
        0x17,                // ldc_i4_1
        0x2a                // ret
    };

    // Get the token for the method whose body you are replacing.
    MethodToken somemethodToken = somemethod.GetToken();

    // Get the pointer to the method body.
        GCHandle hmem = GCHandle.Alloc((Object) methodBytes, GCHandleType.Pinned);
        IntPtr addr = hmem.AddrOfPinnedObject();
    int cbSize = methodBytes.Length;

    // Swap the old method body with the new body.
    MethodRental.SwapMethodBody(
                    tbBaked,
                    somemethodToken.Token,
                    addr,
                    cbSize,
                    MethodRental.JitImmediate);

    // Verify that the modified method returns 1.
    int res2 = (int)tbBaked.GetMethod("My method Name").Invoke( null, new Object[]{} );
    if ( res2 != 1 ) {
        Console.WriteLine( "Err_001b, should have returned 1" );
    } else {
        Console.WriteLine("Swapped method body returned 1");
    }
    }
}

Imports System.Reflection
Imports System.Reflection.Emit
Imports System.Runtime.InteropServices

Class SwapMethodBodySample
    
    ' First make a method that returns 0.
    ' Then swap the method body with a body that returns 1.
    Public Shared Sub Main()
        ' Construct a dynamic assembly
        Dim g As Guid = Guid.NewGuid()
        Dim asmname As New AssemblyName()
        asmname.Name = "tempfile" + g.ToString()
        Dim asmbuild As AssemblyBuilder = _
           System.Threading.Thread.GetDomain().DefineDynamicAssembly _
           (asmname, AssemblyBuilderAccess.Run)
        
        ' Add a dynamic module that contains one type that has one method that
        ' has no arguments.
        Dim modbuild As ModuleBuilder = asmbuild.DefineDynamicModule("test")
        Dim tb As TypeBuilder = modbuild.DefineType("name of the Type")
        Dim somemethod As MethodBuilder = _
           tb.DefineMethod("My method Name", _
           MethodAttributes.Public Or(MethodAttributes.Static), _
           GetType(Integer), New Type() {})
        ' Define the body of the method to return 0.
        Dim ilg As ILGenerator = somemethod.GetILGenerator()
        ilg.Emit(OpCodes.Ldc_I4_0)
        ilg.Emit(OpCodes.Ret)
        
        ' Complete the type and verify that it returns 0.
        Dim tbBaked As Type = tb.CreateType()
        Dim res1 As Integer = _
           CInt(tbBaked.GetMethod("My method Name").Invoke _
           (Nothing, New Object() {}))
        If res1 <> 0 Then
            Console.WriteLine("Err_001a, should have returned 0")
        Else
            Console.WriteLine("Original method returned 0")
        End If
        
        ' Define a new method body that will return a 1 instead.
        Dim methodBytes As Byte() = _
        {&H3, &H30, &HA, &H0, &H2, &H0, &H0, &H0, &H0, &H0, &H0, &H0, &H17, &H2A}
        '&H2     code size
        '&H17    ldc_i4_1
        '&H2A    ret
        
        ' Get the token for the method whose body you are replacing.
        Dim somemethodToken As MethodToken = somemethod.GetToken()
        
        ' Get the pointer to the method body.
        Dim hmem As GCHandle = _
           GCHandle.Alloc(CType(methodBytes, Object), GCHandleType.Pinned)
        Dim addr As IntPtr = hmem.AddrOfPinnedObject()
        Dim cbSize As Integer = methodBytes.Length
        
        ' Swap the old method body with the new body.
        MethodRental.SwapMethodBody(tbBaked, somemethodToken.Token, addr, _
           cbSize, MethodRental.JitImmediate)
        
        ' Verify that the modified method returns 1.
        Dim res2 As Integer = _
           CInt(tbBaked.GetMethod("My method Name").Invoke _
           (Nothing, New Object() {}))
        If res2 <> 1 Then
            Console.WriteLine("Err_001b, should have returned 1")
        Else
            Console.WriteLine("Swapped method body returned 1")
        End If
    End Sub
End Class

Uwagi

Nie można użyć tej metody do zamiany treści metody globalnej.

Metodę można wywołać tylko przez klienta, który utworzył moduł dynamiczny zawierający typ, którego treść metody jest zamieniana.

Dotyczy

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