부모윈도우를 변경, 캡션변경 (SetParent, SetWindowText)

#include <windows.h>

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

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);
    hWndMain=hWnd;
    
    while(GetMessage(&Message,0,0,0)) {
        TranslateMessage(&Message);
        DispatchMessage(&Message);
    }
    return Message.wParam;
}

HWND hBtn;
#define IDBTN 100
LRESULT CALLBACK WndProc(HWND hWnd,UINT iMessage,WPARAM wParam,LPARAM lParam)
{
    HDC hdc;
    PAINTSTRUCT ps;
    char Mes[]="좌우 마우스 버튼을 눌러 보십시오";

    switch(iMessage) {
    case WM_CREATE:
        hBtn=CreateWindow("button","자식 버튼",
            WS_CHILD | WS_VISIBLE | BS_PUSHBUTTON,
            20,20,100,25,hWnd,(HMENU)IDBTN,g_hInst,NULL);
        return 0;
    case WM_LBUTTONDOWN:
        SetParent(hBtn,GetDesktopWindow());            // hBtn의 부모윈도우 핸들을 바탕화면의 핸들로 정의해버리고
        SetWindowText(hBtn,"가출한 버튼");            // SetWindowText로 hBtn의 caption을 변경한다.
        return TRUE;
    case WM_RBUTTONDOWN:
        SetParent(hBtn,hWnd);                        // hBtn의 handle을 hWnd 즉 현재 윈도우로 변경하고
        SetWindowText(hBtn,"돌아온 버튼");            // caption을 변경한다.
        return TRUE;
    case WM_COMMAND:
        switch (LOWORD(wParam)) {
        case IDBTN:
            MessageBox(hWnd,"버튼을 눌렀습니다.","알림",MB_OK);
        }
        return TRUE;
    case WM_PAINT:
        hdc=BeginPaint(hWnd, &ps);
        TextOut(hdc,20,50,Mes,strlen(Mes));
        EndPaint(hWnd, &ps);
        return 0;
    case WM_DESTROY:
        PostQuitMessage(0);
        return 0;
    }
    return(DefWindowProc(hWnd,iMessage,wParam,lParam));
}