给记事本添加接口，并通过菜单来执行自定义的功能

思路：通过反汇编确定记事本的窗口过程地址，把它替换为我们自己的窗口过程地址，在自己窗口过程中先判断是否是自定义的消息，

是则执行相应的操作，不是则把流程转到记事本原来的窗口过程中进行处理。

添加的功能：转换大小写，加解密文本，统计字数。

源代码编译成DLL

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// ExNotepad.cpp : Defines the entry point for the DLL application.

//

 

#include "stdafx.h"

#include "resource.h"

#include <tchar.h>

 

#define IDR_UPPER   (128)/*转换为大写*/

#define IDR_LOWER   (129)/*转换为小写*/

#define IDR_ENCRYPT (130)/*加解密*/

#define IDR_COUNT   (131)/*计算字数*/

 

HINSTANCE   hDll;

HWND    g_hEdit =   NULL;//编辑框句柄

DWORD   ExWndProc(CONST DWORD Reserved, HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam);

VOID    WINAPI  TO_UPPER(HWND hWnd);//转换到大写

VOID    WINAPI  TO_LOWER(HWND hWnd);//转换到小写

VOID    WINAPI  EnCrypt(HWND hWnd);//简单加密

BOOL    WINAPI  EnCryptProc(HWND hDlg, UINT uMsg, WPARAM wParam, LPARAM lParam);

VOID    WINAPI  OnEnCryptCommand(HWND hDlg, UINT uID, HWND hCtrl, UINT uNotifyCode);

VOID    WINAPI  Count(HWND hWnd);//计算字数

 

BOOL APIENTRY DllMain( HANDLE hModule,

                       DWORD  ul_reason_for_call,

                       LPVOID lpReserved

                     )

{

    hDll    =   (HINSTANCE)hModule;

    return TRUE;

}

 

DWORD   ExWndProc(CONST DWORD Reserved, HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam)

{

    switch (uMsg)

    {

    case WM_COMMAND:

        {

            switch (LOWORD(wParam))

            {

            case IDR_UPPER:

                {

                    TO_UPPER(hWnd);

                }

                break;

            case IDR_LOWER:

                {

                    TO_LOWER(hWnd);

                }

                break;

            case IDR_ENCRYPT:

                {

                    EnCrypt(hWnd);

                }

                break;

            case IDR_COUNT:

                {

                    Count(hWnd);

                }

                break;

            }

         

        }

        break;

    }

 

    return 0;

}

 

VOID    WINAPI  TO_UPPER(HWND hWnd)

{

    //读取编辑框句柄

    if (g_hEdit = GetDlgItem(hWnd, 0xF))

    {

        INT len =   GetWindowTextLength(g_hEdit);

         

        if (len > 0)

        {

            LPTSTR  pstrBuffer  =   new TCHAR[len+2];

            memset(pstrBuffer, 0, sizeof(TCHAR)*(len+2));

            GetWindowText(g_hEdit, pstrBuffer, len+2);

            SendMessage(g_hEdit, EM_SETMODIFY, (WPARAM)TRUE, 0);

            CharUpper(pstrBuffer);

            SetWindowText(g_hEdit, pstrBuffer);

            delete  []pstrBuffer;

        }

    }

}

 

VOID    WINAPI  TO_LOWER(HWND hWnd)

{

    //读取编辑框句柄

    if (g_hEdit = GetDlgItem(hWnd, 0xF))

    {

        INT len =   GetWindowTextLength(g_hEdit);

         

        if (len > 0)

        {

            LPTSTR  pstrBuffer  =   new TCHAR[len+2];

            memset(pstrBuffer, 0, sizeof(TCHAR)*(len+2));

            GetWindowText(g_hEdit, pstrBuffer, len+2);

            SendMessage(g_hEdit, EM_SETMODIFY, (WPARAM)TRUE, 0);

            CharLower(pstrBuffer);

            SetWindowText(g_hEdit, pstrBuffer);

            delete  []pstrBuffer;

        }

    }

}

 

VOID    WINAPI  EnCrypt(HWND hWnd)

{

    if (g_hEdit = GetDlgItem(hWnd, 0xF))

    {

        INT len =   GetWindowTextLength(g_hEdit);

         

        if (len > 0)

        {

            DialogBoxParam(hDll, MAKEINTRESOURCE(IDD_DLG_ENCRYPT), hWnd, EnCryptProc, NULL);

        }

    }

}

 

BOOL    WINAPI  EnCryptProc(HWND hDlg, UINT uMsg, WPARAM wParam, LPARAM lParam)

{

    switch (uMsg)

    {

    case WM_CLOSE:

        EndDialog(hDlg, 0);

        break;

    case WM_COMMAND:

        {

            OnEnCryptCommand(hDlg, LOWORD(wParam), (HWND)lParam, HIWORD(wParam));

        }

        break;

    default:

        return  FALSE;

    }

 

    return  TRUE;

}

 

VOID    WINAPI  OnEnCryptCommand(HWND hDlg, UINT uID, HWND hCtrl, UINT uNotifyCode)

{

    switch (uID)

    {

    case IDC_BTN_ENCRYPT://加密

        {

            HWND    hEncryptEdit    =   GetDlgItem(hDlg, IDC_EDT_KEY);

            INT nKeyLen =   GetWindowTextLength(hEncryptEdit);

             

            if (nKeyLen > 0)

            {

                LPTSTR  pstrKey =   new TCHAR[nKeyLen+2];

                memset(pstrKey, 0, nKeyLen+2);

                GetWindowText(hEncryptEdit, pstrKey, nKeyLen+2);

                 

                INT len =   GetWindowTextLength(g_hEdit);

 

                LPTSTR  pstrText    =   new TCHAR[len+2];

                memset(pstrText, 0, len+2);

                GetWindowText(g_hEdit, pstrText, len+2);

                SendMessage(g_hEdit, EM_SETMODIFY, (WPARAM)TRUE, 0);

                 

                DWORD dwKey =   0;

 

                for (INT j = 0; j < nKeyLen; j++)

                {

                    dwKey   +=  pstrKey[j];

                }

                 

                dwKey   %=  32;

 

                for (INT i = 0; i < len; i++)

                {

                    pstrText[i] -=  (TCHAR)dwKey;

                }          

                 

                SetWindowText(g_hEdit, pstrText);

                delete  []pstrText;

                delete  []pstrKey;

            }

        }

        break;

    case IDC_BTN_DECRYPT://解密

        {

            HWND    hEncryptEdit    =   GetDlgItem(hDlg, IDC_EDT_KEY);

            INT nKeyLen =   GetWindowTextLength(hEncryptEdit);

             

            if (nKeyLen > 0)

            {

                LPTSTR  pstrKey =   new TCHAR[nKeyLen+2];

                memset(pstrKey, 0, nKeyLen+2);

                GetWindowText(hEncryptEdit, pstrKey, nKeyLen+2);

                SendMessage(g_hEdit, EM_SETMODIFY, (WPARAM)TRUE, 0);

                 

                INT len =   GetWindowTextLength(g_hEdit);

 

                LPTSTR  pstrText    =   new TCHAR[len+2];

                memset(pstrText, 0, len+2);

                GetWindowText(g_hEdit, pstrText, len+2);

                 

                DWORD dwKey =   0;

 

                for (INT j = 0; j < nKeyLen; j++)

                {

                    dwKey   +=  pstrKey[j];

                }

                 

                dwKey   %=  32;

 

                for (INT i = 0; i < len; i++)

                {

                    pstrText[i] +=  (TCHAR)dwKey;

                }          

                 

                SetWindowText(g_hEdit, pstrText);

                delete  []pstrText;

                delete  []pstrKey;

            }

        }

        break;

    }

 

    return;

}

 

VOID    WINAPI  Count(HWND hWnd)

{

    if (g_hEdit = GetDlgItem(hWnd, 0xF))

    {

        INT len =   GetWindowTextLength(g_hEdit);

         

        if (len > 0)

        {

            TCHAR   strText[MAX_PATH];

            memset(strText, 0, sizeof(TCHAR)*MAX_PATH);

            wsprintf(strText, _T("当前总字数为: %d"), len);

            MessageBox(hWnd, strText, _T("字数统计"), MB_OK);

        }

    }

}