列表中的选项可以在呈现后更改吗？(Can choices in a list be changed after it has been been rendered?)

 这可以通过以下方式完成： 
 
 http://www.lenholgate.com/blog/2009/07/error-cannot-pass-a-gchandle-across-appdomains.html 
 
 总结解决方案： 
 
 
 
 诀窍是你需要使用一个委托，它知道它与之相关的AppDomain，然后通过将委托转换为函数指针来调用委托。 这有效地将非托管调用封送到正确的AppDomain中，然后再执行托管c 
 
 
 将解决方案应用于您的代码，它按预期编译和执行： 
 
#include "stdafx.h"
#include <Windows.h>
#include <msclr/gcroot.h>

using namespace System;
using namespace System::Runtime::InteropServices;

#pragma unmanaged

class IService
{
public:
    virtual void Operate() = 0;
};

DWORD __stdcall MyNativeThread(LPVOID arg)
{
    IService* service = (IService*)arg;

    service->Operate();

    return 0;
}

void StartNativeThread(IService* service)
{
    CloseHandle(CreateThread(NULL, 0, &MyNativeThread, service, 0, NULL));
}

#pragma managed 

typedef void (__stdcall ConnectFnc)();

public ref class ServiceManagedImpl
{
public:
    ServiceManagedImpl()
    {
        m_OperateDelegate = gcnew Delegate(this, &ServiceManagedImpl::Operate);
    }
    ConnectFnc *GetDelegateFunctionPointer()
    {
        return   (ConnectFnc*)(Marshal::GetFunctionPointerForDelegate(m_OperateDelegate).ToPointer());
    }

public:
    void Operate()
    {
        System::Console::WriteLine("ServiceManagedImpl::Operate: Domain: {0}", System::AppDomain::CurrentDomain->Id);
    }
private:
    delegate void Delegate();
    Delegate ^m_OperateDelegate;
};

class ServiceImpl : public IService
{
public:
    ServiceImpl(ServiceManagedImpl^ managedImpl)
    {
        m_managedImpl = new msclr::gcroot<ServiceManagedImpl^>(managedImpl);   
        m_pFunction = (*m_managedImpl)->GetDelegateFunctionPointer();
    }
    ~ServiceImpl()
    {
        delete m_managedImpl;
    }
    void operator()() const
    {
        m_pFunction();
    }

    virtual void Operate() override
    {
        m_pFunction();
    }

private:
    msclr::gcroot<ServiceManagedImpl^> *m_managedImpl;
    ConnectFnc *m_pFunction;
};

public ref class MyMmcSnapIn : MarshalByRefObject
{
public:
    MyMmcSnapIn()
    {
        System::Console::WriteLine("MyMmcSnapIn.ctor: Domain: {0}", AppDomain::CurrentDomain->Id);

        ServiceImpl testImpl = ServiceImpl(gcnew ServiceManagedImpl());

        StartNativeThread(&testImpl);

        Threading::Thread::Sleep(10000);
    }
};

int main()
{
    Console::WriteLine(L"Main: Domain: {0}", AppDomain::CurrentDomain->Id);

    AppDomain^ mmcSnapInAppDomain = AppDomain::CreateDomain("AppDomainForMyMmcSnapIn");

    // direct instantiation works as expected
    // gcnew MyMmcSnapIn();

    String^ entryAssemblyLocation = Reflection::Assembly::GetEntryAssembly()->Location;
    mmcSnapInAppDomain->CreateInstanceFrom(entryAssemblyLocation, "MyMmcSnapIn");

    return 0;
}

This could be done the way is suggested here:
 
http://www.lenholgate.com/blog/2009/07/error-cannot-pass-a-gchandle-across-appdomains.html
 
To summarize the solution: 
 
 
 
The trick is that you need to use a delegate, which knows about the AppDomain that it relates to, and then call through the delegate by converting it to a function pointer. This effectively marshals the unmanaged call into the correct AppDomain before executing the managed c
 
 
Applying the solution to your code, it compiles and executes as expected:
 
#include "stdafx.h"
#include <Windows.h>
#include <msclr/gcroot.h>

using namespace System;
using namespace System::Runtime::InteropServices;

#pragma unmanaged

class IService
{
public:
    virtual void Operate() = 0;
};

DWORD __stdcall MyNativeThread(LPVOID arg)
{
    IService* service = (IService*)arg;

    service->Operate();

    return 0;
}

void StartNativeThread(IService* service)
{
    CloseHandle(CreateThread(NULL, 0, &MyNativeThread, service, 0, NULL));
}

#pragma managed 

typedef void (__stdcall ConnectFnc)();

public ref class ServiceManagedImpl
{
public:
    ServiceManagedImpl()
    {
        m_OperateDelegate = gcnew Delegate(this, &ServiceManagedImpl::Operate);
    }
    ConnectFnc *GetDelegateFunctionPointer()
    {
        return   (ConnectFnc*)(Marshal::GetFunctionPointerForDelegate(m_OperateDelegate).ToPointer());
    }

public:
    void Operate()
    {
        System::Console::WriteLine("ServiceManagedImpl::Operate: Domain: {0}", System::AppDomain::CurrentDomain->Id);
    }
private:
    delegate void Delegate();
    Delegate ^m_OperateDelegate;
};

class ServiceImpl : public IService
{
public:
    ServiceImpl(ServiceManagedImpl^ managedImpl)
    {
        m_managedImpl = new msclr::gcroot<ServiceManagedImpl^>(managedImpl);   
        m_pFunction = (*m_managedImpl)->GetDelegateFunctionPointer();
    }
    ~ServiceImpl()
    {
        delete m_managedImpl;
    }
    void operator()() const
    {
        m_pFunction();
    }

    virtual void Operate() override
    {
        m_pFunction();
    }

private:
    msclr::gcroot<ServiceManagedImpl^> *m_managedImpl;
    ConnectFnc *m_pFunction;
};

public ref class MyMmcSnapIn : MarshalByRefObject
{
public:
    MyMmcSnapIn()
    {
        System::Console::WriteLine("MyMmcSnapIn.ctor: Domain: {0}", AppDomain::CurrentDomain->Id);

        ServiceImpl testImpl = ServiceImpl(gcnew ServiceManagedImpl());

        StartNativeThread(&testImpl);

        Threading::Thread::Sleep(10000);
    }
};

int main()
{
    Console::WriteLine(L"Main: Domain: {0}", AppDomain::CurrentDomain->Id);

    AppDomain^ mmcSnapInAppDomain = AppDomain::CreateDomain("AppDomainForMyMmcSnapIn");

    // direct instantiation works as expected
    // gcnew MyMmcSnapIn();

    String^ entryAssemblyLocation = Reflection::Assembly::GetEntryAssembly()->Location;
    mmcSnapInAppDomain->CreateInstanceFrom(entryAssemblyLocation, "MyMmcSnapIn");

    return 0;
}