c++ - LNK 2001 : unresolved external symbol while initializing static member

Question

我正在尝试实现一个虚拟键盘类，因为我有不同的键盘布局，如图所示。

键盘.hpp

 class CKeyBoard 
 {
    public:

    enum eKeyBoardLayout
    {
        UPPER_CASE_ALPHABETS,
        LOWER_CASE_ALPHABETS,
        UPPER_CASE_NUMBERS,
        LOWER_CASE_NUMBERS,
        MAX_KEYBOARDLAYOUTS,
    };
    CKeyBoard();
    void hideCharacters(bool hide); // for password
    void setDisplayBufferLength(UNSIGNED8_T maxCharToDisplay);
    virtual ~CKeyBoard();
    static const UNSIGNED8_T const_noOfRows = 0x03; // 3 rows for character keys
    struct SLayout
    {
        UNSIGNED8_T noOfColumns[const_noOfRows];    ///< noofcolumns in each row may be different
        TypedText     textAreaFont; 
        const KeyMapping* pKeyMapping;
    };
    static const SLayout m_KeyBoardLayouts[MAX_KEYBOARDLAYOUTS];
private:
    /*methods*/
    void setKeyBoardLayout(eKeyBoardLayout);
    void backspacePressedHndlr();
    void letterCasePressedHndlr();
    void alphabetNumberToggleHndlr();
    /*members*/
    static const UNSIGNED8_T const_maxNoOfKeysSupprtd = 26;
    CKey m_keyArray[const_maxNoOfKeysSupprtd]; 
    CMenuItem m_KeySpaceBar;
    CMenuToggle m_KeyCaseSwitch;
    CMenuToggle m_KeyAlphaNum;
    CMenuItem m_keyBackSpace;
    eKeyBoardLayout m_eCurrentKeyLayout;
    CKeyBoardDisplayArea m_DisplayArea;

};

我正在 cpp 文件中初始化静态成员，如下所示。键盘.cpp

static const CKeyBoard::SLayout   m_KeyBoardLayouts[CKeyBoard::MAX_KEYBOARDLAYOUTS] = \
  {
      //      UPPER_CASE_ALPHABETS,
    {
      { 10, 9, 7 },
        TypedText(T_KEYBOARD),
        &keyMappingsAlphaUpper[0],

},
//      LOWER_CASE_ALPHABETS,
{
    { 10, 9, 7 },
    TypedText(T_KEYBOARD),
    &keyMappingsAlphaLower[0],
},
//      UPPER_CASE_NUMBERS,
{
    { 10, 10, 5 },
    TypedText(T_KEYBOARD),
    &keyMappingsNumLower[0],
},
//      LOWER_CASE_NUMBERS,
{
    { 10, 10, 5 },
    TypedText(T_KEYBOARD),
    &keyMappingsNumLower[0]
},


};
// Other function definitions
CKey::CKey() : m_pCallback(NULL)
{
}

但我仍然收到未解析的外部符号作为链接器错误。我在这里做错了什么？

错误详情:*error LNK2001: 未解析的外部符号“public: static struct CKeyBoard::SLayout const * const CKeyBoard::m_KeyBoardLayouts” (?m_KeyBoardLayouts@CKeyBoard@@2QBUSLayout@1@B)*

Answer 1

您忘记添加类范围:

static const CKeyBoard::SLayout   
    CKeyBoard::m_KeyBoardLayouts[CKeyBoard::MAX_KEYBOARDLAYOUTS]

遗憾的是编译器没有像那样警告静态链接......这是一个常见的错误。