【Demo 0022】改变窗体大小和位置

窗体有三个最基本的属性：位置，大小，Z-Order， Windows 对于改变窗体位置和大小这两个更常用提供了更简单的函数.

（一）改变窗体大小和位置

BOOL MoveWindow(HWND hWnd, int x, int y, int nWidth, int nHeight, BOOL bRepaint)

改变指定窗体的起始位置以及窗体大小，最后一个参数是改变是否重绘窗体

以下代码演示了将窗体置桌面客户区中间，以及将控件置于窗体客户区中间并放大一倍

 UINT nSrnWidth    = GetSystemMetrics(SM_CXFULLSCREEN);
 UINT nSrnHeight    = GetSystemMetrics(SM_CYFULLSCREEN);
 
 RECT rtWnd;
 GetWindowRect(hWnd, &rtWnd);
 UINT nWndWidth    = (rtWnd.right - rtWnd.left);
 UINT nWndHeight = (rtWnd.bottom - rtWnd.top);
 MoveWindow(hWnd, (nSrnWidth - nWndWidth) / 2, (nSrnHeight - nWndHeight) / 2, nWndWidth, nWndHeight, TRUE);
 
 HWND hBtnMove = GetDlgItem(hWnd, wParam);
 UINT nBtnWidth    = 200;
 UINT nBtnHeight = 100;
 MoveWindow(hBtnMove, (nWndWidth - nBtnWidth) / 2, (nWndHeight - nBtnHeight) / 2, nBtnWidth, nBtnHeight, TRUE);

（二）改变窗体大小和位置触发的消息

1. WM_WINDOWPOSCHANGING
2. WM_WINDOWPOSCHANGED

3. WM_MOVE

4. WM_SIZE
5. WM_NCCALCSIZE

 case WM_WINDOWPOSCHANGING:
 {
     TCHAR szInfo[128];
     _stprintf(szInfo, _T("Step %d:        WM_WINDOWPOSCHANGING\n"), ++nStep);
     OutputDebugString(szInfo);
     break;
 }
 case WM_WINDOWPOSCHANGED:
 {
     TCHAR szInfo[128];
     _stprintf(szInfo, _T("Step %d:        WM_WINDOWPOSCHANGED\n"), ++nStep);
     OutputDebugString(szInfo);
     break;
 }
 case WM_MOVE:
 {
     TCHAR szInfo[128];
     _stprintf(szInfo, _T("Step %d:        WM_MOVE\n"), ++nStep);
     OutputDebugString(szInfo);
     break;    
 }
 case WM_SIZE:
 {
     TCHAR szInfo[128];
     _stprintf(szInfo, _T("Step %d:        WM_SIZE\n"), ++nStep);
     OutputDebugString(szInfo);
     break;
 }
 case WM_NCCALCSIZE:
 {
     TCHAR szInfo[128];
     _stprintf(szInfo, _T("Step %d:        WM_NCCALCSIZE\n"), ++nStep);
     OutputDebugString(szInfo);
     break;
 }

程序启动时结果:

      Step 1:        WM_NCCALCSIZE
      Step 2:        WM_SIZE
      Step 3:        WM_MOVE
      Step 4:        WM_WINDOWPOSCHANGING
      Step 5:        WM_WINDOWPOSCHANGING
      Step 6:        WM_WINDOWPOSCHANGED

移动窗体后结果：

Step 71:        WM_WINDOWPOSCHANGING
 Step 72:        WM_WINDOWPOSCHANGED
 Step 73:        WM_MOVE
 Step 74:        WM_WINDOWPOSCHANGING
 Step 75:        WM_WINDOWPOSCHANGED
 Step 76:        WM_MOVE
 Step 77:        WM_WINDOWPOSCHANGING
 Step 78:        WM_WINDOWPOSCHANGED
 Step 79:        WM_MOVE
 Step 80:        WM_WINDOWPOSCHANGING

演示代码