Ice::UnknownException happend when Pass a std::string parameter in a function

senses1

I develop a server using VC++ MFC ，and a client using c#，
I define .ice file below

module UIServerInteract
{
//GUI界面需要实现的接口，供后台软件调用
interface IServerEvent
{
//向对话显示区中新增问题
void NewQuestionAdd(string strQuestion);

    //向对话显示区中新增问题
    void NewAnswerAdd(int iType, string strAnswer);

    //退出应用
    void ExitApp();

    //TestInterface
    void Test(int itype);
};
//后台软件需要实现的接口，供UI调用
interface BGServer
{
    bool Login(string strUser,IServerEvent* pSvrEvent);
    void Logout(string strUser);
};

};

when I call NewQuestionAdd(string strQuestion) function like
m_UISvrPrx->NewQuestionAdd("1212");
in server ,it throws a Ice::UnknownException, but the string value has been shown in client.
but I call Test(int itype) function , no exception happens.
when call Login(string strUser,IServerEvent* pSvrEvent) funtion in client , no exception happens.

my question is: is there a special string code page when passing the parameter?
how this exception happen?
I've tried 3.4.2, 3.6.3 &3.70b version,3.4.2 does not work properly at all, but last two throws exception.
i am using win7 & vs2015 community.

senses1

Any one got idea?who can help me?

benoit

Hi,

Sounds like the C++ server isn't sending a valid UTF-8 string to the C# client.

Where do you get the Ice::UnknownException exception? In the C# client or C++ server? Is it the C++ server which is making the call? The exception has an unknown data member, you should try printing out this data member to see the cause of the exception.

// C#
try
{
     ...
}
catch(Ice.UnknownException ex)
{
    System.Console.WriteLine("unknown exception:\n" + ex.unknown);
}

In C++, you should use a string converter if you want to use strings encoded with a native encoding with the Ice APIs. The string converter will convert the native string to UTF-8 before sending it.

See https://doc.zeroc.com/pages/viewpage.action?pageId=16716075 for more information on C++ string converters.

Cheers,
Benoit.

senses1

I've been busy at other projecct for several days , sorry for that long time.
my server break to exception.
I called function in c++ server like this

if (NULL != m_UISvrPrx)
    {
        try
        {
            string utfstr = AnsiToUtf8(strQuestion);
            m_UISvrPrx->NewQuestionAdd(AnsiToUtf8(strQuestion));//this line will triger exception
        }
        catch (Ice::UnknownException* e)
        {
            _RPT1(_CRT_WARN,"exception happend : %s\n",e->unknown);
        }
    }

but it always break to exception in below code line:__invoke(__og);

void
IceProxy::UIServerInteract::IServerEvent::NewQuestionAdd(const ::std::string& __p_strQuestion, const ::Ice::Context* __ctx)
{
    ::IceInternal::Outgoing __og(this, __UIServerInteract__IServerEvent__NewQuestionAdd_name, ::Ice::Normal, __ctx);
    try
    {
        ::IceInternal::BasicStream* __os = __og.startWriteParams(::Ice::DefaultFormat);
        __os->write(__p_strQuestion);
        __og.endWriteParams();
    }
    catch(const ::Ice::LocalException& __ex)
    {
        __og.abort(__ex);
    }
    __invoke(__og);//this line is the last position exception break to
}

it never log to output the exception info.
I tried to continue the C++ Server and the c# client can view the string pass to it ,and the server always break to exception.

benoit

Hi,

Sorry, but it's still no clear to me what's happening. If I understanding it correct, the NewQuestionAdd is dispatched on the C# client but it raises an exception. Can you provide the type and stack of the exception which has been raised?

Cheers,
Benoit.

senses1

I've solved the problem. The exception does not caused by Ice.The source is c# client function changes UI control value directly,where it is not allowed in c# winform project called thread cross calling.
thank you all the same @ Benoit Foucher .