Question

大家新年快乐等。

我无法使用模板化某些函数指针：

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下遇到此错误：

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

不是很具描述性。我甚至想做什么？任何提示都会受到欢迎！感谢。

Answer 1

要修复代码，请使用typename：

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

有关详细信息，请查看template dependent names

模板化函数指向成员函数的指针

1 个答案: