函数类型作为模板的类型参数，could not deduce template argument for 'T'

Question

模板定义：

template <typename UnaryFunction, typename ContextAcessor>
void ForEachApplication(UnaryFunction func) {
    using namespace utils;
    typename ContextAcessor::ApplicationListAccessor accessor;
    typedef typename ContextAcessor::ApplictionSetConstIt Iter;
    for (Iter it = accessor.begin(); it != accessor.end(); ++it) {
        if (it->valid()) {
            ApplicationConstSharedPtr const_app = *it;
            func(ContextAcessor::instance()->application(const_app->app_id()));
        }
    }
}

模板调用：

void StateController::TempStateStopped(HmiState::StateID ID) {
    LOG4CXX_AUTO_TRACE(logger_);
    {
        sync_primitives::AutoLock autolock(active_states_lock_);
        active_states_.remove(ID);
    }

    ForEachApplication(std::bind1st(std::mem_fun(&StateController::ApplyPostponedStateForApp), this));
}

编译错误：

error C2783: 'void application_manager::StateController::ForEachApplication(UnaryFunction)' : could not deduce template argument for 'ContextAcessor'

编译环境：win7_x64+vs2008

请大神帮帮忙，怎么解决啊~~~

Answer 1

说的很清楚，没办法推定类型，因为你的函数参数没有ContextAcessor，所以不知道它的类型，需要指定下
http://stackoverflow.com/questions/19221183/could-not-deduce-template-argument-for-t