c++ - 指向成员函数的模板化函数指针

Question

大家好，新年快乐等

我在模板化一些函数指针时遇到了问题:

目前的代码如下:

    template<class T>
    class EventMapper
    {
    private:
        typedef std::wstring const (T::*messageHandler)(std::wstring const & myMessage);                //!< Templated function pointer
        typedef std::tr1::unordered_map<std::wstring, messageHandler> umap;                             //!< abbreviation for eventHandler map container
        typedef umap::const_iterator eventCIt;                                                          //!< abbreviation for event map const_iterator
        typedef umap::iterator  eventIt;                                                                //!< abbreviation for event map iterator

        //test func ptr
        T const & myInstance;
        umap myEventMap;
        eventCIt myCurrentCommand;                                                                      //!< current selected command
    public:
        EventMapper( T const & instance_in) : myInstance(instance_in){}

        //register an event handler
        void registerHandler(std::wstring const & cmd_in, messageHandler handler_in)
        {
            this->myEventMap.insert(umap::value_type(cmd_in, handler_in));
        }

我在 MSVS 2008 SP1 下遇到这个错误:

Error   3   error C2146: syntax error : missing ';' before identifier 'eventCIt'    o:\AX_FusRecAlg\include\Reconstruction\JobListEditor\Types.h    19  AX.Services.Reconstruction.JobListDataProviderTest

描述性不强。我正在尝试做的事情有可能吗？欢迎任何提示!谢谢。

Answer 1

要修复您的代码，请使用 typename :

        typedef typename umap::const_iterator eventCIt;                                                          //!< abbreviation for event map const_iterator
        typedef typename umap::iterator  eventIt;

更多信息，看template dependent names