서브 클래싱

#include <windows.h>

LRESULT CALLBACK WndProc(HWND,UINT,WPARAM,LPARAM);
HINSTANCE g_hInst;
LPSTR lpszClass="SubEdit";

int APIENTRY WinMain(HINSTANCE hInstance,HINSTANCE hPrevInstance
         ,LPSTR lpszCmdParam,int nCmdShow)
{
    HWND hWnd;
    MSG Message;
    WNDCLASS WndClass;
    g_hInst=hInstance;
    
    WndClass.cbClsExtra=0;
    WndClass.cbWndExtra=0;
    WndClass.hbrBackground=(HBRUSH)GetStockObject(WHITE_BRUSH);
    WndClass.hCursor=LoadCursor(NULL,IDC_ARROW);
    WndClass.hIcon=LoadIcon(NULL,IDI_APPLICATION);
    WndClass.hInstance=hInstance;
    WndClass.lpfnWndProc=(WNDPROC)WndProc;
    WndClass.lpszClassName=lpszClass;
    WndClass.lpszMenuName=NULL;
    WndClass.style=CS_HREDRAW | CS_VREDRAW;
    RegisterClass(&WndClass);
    
    hWnd=CreateWindow(lpszClass,lpszClass,WS_OVERLAPPEDWINDOW,
        CW_USEDEFAULT,CW_USEDEFAULT,CW_USEDEFAULT,CW_USEDEFAULT,
        NULL,(HMENU)NULL,hInstance,NULL);
    ShowWindow(hWnd,nCmdShow);
    
    while(GetMessage(&Message,0,0,0)) {
        TranslateMessage(&Message);
        DispatchMessage(&Message);
    }
    return Message.wParam;
}

#define ID_EDIT1 100
#define ID_EDIT2 101
HWND hEdit1, hEdit2;
WNDPROC OldEditProc;
LRESULT CALLBACK EditSubProc(HWND hWnd,UINT iMessage,WPARAM wParam,LPARAM lParam)
{
    switch (iMessage) {
    case WM_KEYDOWN:
        if (wParam==VK_RETURN) {
            MessageBox(hWnd,"Enter is Pressed","Edit",MB_OK);
            SetFocus(hWnd);
        }
        if (wParam==VK_TAB) {
            SetFocus(hEdit2);
        }
        break;
//    case WM_LBUTTONDOWN:
//        SendMessage(hWnd,EM_SETSEL,0,-1);
//        return 0;
    }
    return CallWindowProc(OldEditProc,hWnd,iMessage,wParam,lParam);
}

LRESULT CALLBACK WndProc(HWND hWnd,UINT iMessage,WPARAM wParam,LPARAM lParam)
{
    PAINTSTRUCT ps;
    HDC hdc;
    char Mes[]="에디트의 Enter키 입력을 검출합니다";
    switch(iMessage) {
    case WM_CREATE:
        hEdit1=CreateWindow("edit",NULL,WS_CHILD | WS_VISIBLE | WS_BORDER |
            ES_AUTOHSCROLL,
            10,10,200,25,hWnd,(HMENU)ID_EDIT1,g_hInst,NULL);
        hEdit2=CreateWindow("edit",NULL,WS_CHILD | WS_VISIBLE | WS_BORDER |
            ES_AUTOHSCROLL,
            10,50,200,25,hWnd,(HMENU)ID_EDIT2,g_hInst,NULL);
        SetFocus(hEdit1);
        OldEditProc=(WNDPROC)SetWindowLong(hEdit1,GWL_WNDPROC,(LONG)EditSubProc);
        return 0;
    case WM_PAINT:
        hdc=BeginPaint(hWnd, &ps);
        TextOut(hdc,10,100,Mes,strlen(Mes));
        EndPaint(hWnd, &ps);
        return 0;
    case WM_DESTROY:
        SetWindowLong(hEdit1,GWL_WNDPROC,(LONG)OldEditProc);
        PostQuitMessage(0);
        return 0;
    }
    return(DefWindowProc(hWnd,iMessage,wParam,lParam));
}