VC++: 使用Thunk技术封装类CDialogBase

#pragma once

class CDialogBase
{
public:
    CDialogBase(DWORD idDlg, HWND hWndParent = NULL);
    ~CDialogBase();

    HWND m_hDlg;
    HWND m_hWndParent;
    BOOL CreateDlg();
    virtual LRESULT WndProc(UINT message, WPARAM wParam, LPARAM lParam);
    LRESULT DoModal();
private:
    LPCWSTR m_lpTemplateName;
    
#pragma pack(push,1)
    typedef struct _StdCallThunk
    {
        DWORD m_mov;        // = 0x042444C7
        DWORD m_this;       // = this
        BYTE m_jmp;         // = 0xe9
        DWORD m_relproc;    // = relative distance
    } StdCallThunk;
#pragma pack(pop)

    StdCallThunk *m_pStdthunk;
    static LRESULT CALLBACK StaticWndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam);
};

 #include "stdafx.h"
#include "DialogBase.h"

CDialogBase::CDialogBase(DWORD idDlg, HWND hWndParent){
    m_pStdthunk = (StdCallThunk *)VirtualAlloc(NULL, sizeof(StdCallThunk), 
        MEM_RESERVE | MEM_COMMIT, PAGE_EXECUTE_READWRITE);

    m_hWndParent = hWndParent;
    m_lpTemplateName = MAKEINTRESOURCE(idDlg);
    m_hDlg = NULL;
}

CDialogBase::~CDialogBase(){
    VirtualFree(m_pStdthunk, sizeof(StdCallThunk), MEM_RELEASE);
}

BOOL CDialogBase::CreateDlg(){
    m_hDlg = CreateDialog(GetModuleHandle(NULL), m_lpTemplateName, m_hWndParent, (DLGPROC)DefWindowProc);

    if (m_hDlg == NULL)
    {
        return FALSE;
    }

    m_pStdthunk->m_mov = 0x042444c7;
    m_pStdthunk->m_jmp = 0xe9;
    m_pStdthunk->m_this = (DWORD)this;
    m_pStdthunk->m_relproc = (DWORD)StaticWndProc - ((DWORD)m_pStdthunk + sizeof(StdCallThunk));
    SetWindowLong(m_hDlg, GWL_WNDPROC, (LONG)m_pStdthunk);

    return TRUE;
}

LRESULT CALLBACK CDialogBase::StaticWndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam){
    return ((CDialogBase *)hWnd)->WndProc(message, wParam, lParam);
}

LRESULT CDialogBase::WndProc(UINT message, WPARAM wParam, LPARAM lParam){
    return DefWindowProc(m_hDlg, message, wParam, lParam);
}

LRESULT CDialogBase::DoModal(){
    if (m_hDlg == NULL)
    {
        CreateDlg();
    }

    EnableWindow(m_hWndParent, FALSE);

    ShowWindow(m_hDlg, SW_SHOW);
    UpdateWindow(m_hDlg);

    return TRUE;
}