c++ - 无法修复 C++ 中的链接器错误

Question

我正在做一个对我来说很新的项目。我对 C++ 有非常基本的了解，但我无法修复尝试在 VC++ 中构建项目时遇到的链接器错误。以下是涉及的2个类的错误和定义。

1>Dlg_Container_View.obj : error LNK2019: unresolved external symbol "public: virtual __thiscall CPictureCtrl::~CPictureCtrl(void)" (??1CPictureCtrl@@UAE@XZ) referenced in function __unwindfunclet$??0CDlg_Container_View@@QAE@PAVCWnd@@@Z$0
1>Dlg_Container_View.obj : error LNK2019: unresolved external symbol "public: __thiscall CPictureCtrl::CPictureCtrl(void)" (??0CPictureCtrl@@QAE@XZ) referenced in function "public: __thiscall CDlg_Container_View::CDlg_Container_View(class CWnd *)" (??0CDlg_Container_View@@QAE@PAVCWnd@@@Z)
1>Dlg_Container_View.obj : error LNK2019: unresolved external symbol "public: int __thiscall CPictureCtrl::Load(class ATL::CStringT<char,class StrTraitMFC_DLL<char,class ATL::ChTraitsCRT<char> > > &)" (?Load@CPictureCtrl@@QAEHAAV?$CStringT@DV?$StrTraitMFC_DLL@DV?$ChTraitsCRT@D@ATL@@@@@ATL@@@Z) referenced in function "protected: virtual int __thiscall CDlg_Container_View::OnInitDialog(void)" (?OnInitDialog@CDlg_Container_View@@MAEHXZ)
1>.\Debug/EDiscovery.exe : fatal error LNK1120: 3 unresolved externals

以下是类定义(我认为它们是相关的。我刚刚复制粘贴了可能无关紧要但我不想错过任何内容的完整定义)。抱歉这个基本问题。

class CPictureCtrl :
    public CStatic
{
public:

    //Constructor
    CPictureCtrl(void);

    //Destructor
    ~CPictureCtrl(void);

public:

    //Loads an image from a file
    BOOL LoadFromFile(CString &szFilePath);

    //Loads an image from an IStream interface
    BOOL LoadFromStream(IStream* piStream);

    //Loads an image from a byte stream;
    BOOL LoadFromStream(BYTE* pData, size_t nSize);

    //Loads an image from a Resource
//  BOOL LoadFromResource(HMODULE hModule, LPCTSTR lpName, LPCTSTR lpType);

    //Overload - Single load function
    BOOL Load(CString &szFilePath);
    BOOL Load(IStream* piStream);
    BOOL Load(BYTE* pData, size_t nSize);
//  BOOL Load(HMODULE hModule, LPCTSTR lpName, LPCTSTR lpType);

    //Frees the image data
    void FreeData();

protected:
    virtual void PreSubclassWindow();

    //Draws the Control
    virtual void DrawItem(LPDRAWITEMSTRUCT lpDrawItemStruct);
    virtual BOOL OnEraseBkgnd(CDC* pDC);



private:

    //Internal image stream buffer
    IStream* m_pStream;

    //Control flag if a pic is loaded
    BOOL m_bIsPicLoaded;

    //GDI Plus Token
    ULONG_PTR m_gdiplusToken;
};

上述类在头文件 PictureCtrl.h 中定义，该文件包含在定义以下类的文件中。以下是将上述类的对象作为成员变量的类:

class CDlg_Container_View : public CDialog , public CParentIView
{
// Construction
public:
    CDlg_Container_View(CWnd* pParent = NULL); 
    ~CDlg_Container_View();
    CDialog * GetDialog(const int idx);
    void ClosePages();
    virtual void SetCurSel(const int idx);
    void AddPage(const char * cText, CDialog * pDlg, const UINT id);
    CPtrArray pPages;
    CStringArray csText;
    CUIntArray csIds;// standard constructor
    int iCurIdx;
    CString csTitle;
    virtual void Show_Dialog();
    virtual void Hide_Dialog();
    virtual void RegisterChildToParent(CString,CIView*);
    virtual void ChangeBtnState(CString p_strBtnName,BOOL flag);
    void SetControlText();
    void ResetDialog();
    void ShowMessageBox(CString msg);
    void EnableProject(bool p_blFlag);
    CFont m_StaticFont;

//  virtual void fun();

    // standard constructor

// Dialog Data
    //{{AFX_DATA(CDlg_Container_View)
    enum { IDD = IDD_DLG_CONTAINER_VIEW_DIALOG };
    CRichEditCtrl   m_REdit_DisplayProjectNots;
    CRichEditCtrl   m_REdit_AddProjectNotes;
    CButton m_Grp_Bx_Project_Notes;
    CButton m_btn_Report;
    CButton m_btn_Export;
    CButton m_btn_Error;
    CStatic m_Lbl_Token_Balance;
    CButton m_Btn_Add_Notes;
    CStatic m_Lbl_Project;
    CButton m_btn_Collect;
    CComboBox   m_Combo_Project_Name;
    CStatic wndFrame;
   CPictureCtrl m_picCtrl; 
    //CHyperLink    m_hyper_Manage_Tokens;
    CStatic m_hyper_Manage_Tokens;
    CHyperLink  m_WebIdHyperlink;
    //}}AFX_DATA


// Overrides
    // ClassWizard generated virtual function overrides
    //{{AFX_VIRTUAL(CDlg_Container_View)
    protected:
    virtual void DoDataExchange(CDataExchange* pDX);    // DDX/DDV support
    //}}AFX_VIRTUAL

// Implementation
protected:
         CBrush m_brush; 
         HICON m_hIcon;
    // Generated message map functions
    //{{AFX_MSG(CDlg_Container_View)
    afx_msg HBRUSH OnCtlColor(CDC* pDC, CWnd* pWnd, UINT nCtlColor);
    virtual BOOL OnInitDialog();
//  afx_msg void OnBtnCollect();
    afx_msg void OnBtnReport();
    afx_msg void OnBtnExport();
    afx_msg void OnBtnClose();
//  afx_msg void OnSelendokCOMBOProjectName();
    afx_msg void OnBtnError();
    afx_msg void OnBtnAddNotes();
    afx_msg void OnEditchangeCOMBOProjectName();
    //}}AFX_MSG
    DECLARE_MESSAGE_MAP()

public:
    CDlg_Container_Presenter *m_objCDlg_Container_Presenter;
    BOOL m_blFirstTime_Collect;
    BOOL m_blEnableButtons;
    CString m_strProjectNote;
    bool m_blFirsttime_Project;


    //bool m_bAutoComplete;
    CString m_sTypedText;

    virtual BOOL PreTranslateMessage(MSG* pMsg);

    afx_msg void OnEnSetfocusReditDisplayprojectnotes();
//  afx_msg void OnCbnDropdownComboProjectName();
    afx_msg void OnBnClickedCheck1();
    afx_msg void OnBnClickedCheck2();
//  afx_msg void OnKeyDown(UINT nChar, UINT nRepCnt, UINT nFlags);
//  afx_msg void OnSysKeyDown(UINT nChar, UINT nRepCnt, UINT nFlags);
//  afx_msg void OnCbnSetfocusComboProjectName();
//  afx_msg void OnCbnEditupdateComboProjectName();

    afx_msg void OnCbnEditupdateComboProjectName();
    afx_msg void OnCbnSelchangeComboProjectName();
    //afx_msg void OnBnClickedBtnProjectEdit();
    afx_msg void OnBnClickedBtnProjectEdit();
//  afx_msg void OnCbnCloseupComboProjectName();
//  afx_msg void OnCbnCloseupComboProjectName();
    afx_msg void OnCbnCloseupComboProjectName();
    afx_msg void OnBnClickedBtnCollect();
    afx_msg void OnCbnSelendokComboProjectName();
    CButton m_btn_Update_Project;
    afx_msg void OnCbnDropdownComboProjectName();
    afx_msg void OnBnClickedButton1();
    afx_msg void OnStnClickedLblManageTokens();
    void UpdateTokenCount();
    CPictureCtrl m_LogoPic;
};

`

Answer 1

那些链接器错误意味着您没有提供这三个函数的定义。即构造函数、析构函数和加载函数...

CPictureCtrl(void);
~CPictureCtrl(void);
BOOL Load(CString &szFilePath);