Win32：子窗口运动受限

Question

我有9个子窗口。现在每个人都可以在父窗口内的任何方向移动。但是我希望中间的那个只向左，向右，向上和向下移动（但不是对角线!!!）并自动对准中心。我无法弄清楚如何实现它。任何帮助表示赞赏。即使在$('form').validate({ messages: { name:"Enter name",email:"Enter email"}, errorPlacement:{ $.notify({ title: "Error:<br>", message: this.message }); } }) 。或者用文字 - 只是解释。

这就是我如何处理子窗口的移动：

C/C++

MoveChildByCenter

.elseif [iMsg] == WM_LBUTTONDOWN

    invoke SetCapture, [hwnd]

    invoke InvalidateRect, [hwnd], 0, TRUE

    xor eax, eax
    ret

.elseif [iMsg] == WM_LBUTTONUP

    invoke ReleaseCapture

    xor eax, eax
    ret

.elseif [iMsg] == WM_MOUSEMOVE

    .if [wParam] & MK_LBUTTON

        movsx eax, word ptr [lParam]
        mov [x], eax
        movsx eax, word ptr [lParam+2]
        mov [y], eax

        invoke GetChildCenter, [hwnd], addr center_x, addr center_y

        mov eax, [x]
        sub eax, CELL_CENTER
        add [center_x], eax

        mov eax, [y]
        sub eax, CELL_CENTER
        add [center_y], eax

        invoke MoveChildByCenter, [hwnd], [center_x], [center_y]

    .endif

    xor eax, eax
    ret

GetChildCenter（相对于父窗口）

MoveChildByCenter proc hwnd:HWND, x:dword, y:dword

    sub [x], CELL_CENTER
    sub [y], CELL_CENTER
    invoke MoveWindow, [hwnd], [x], [y], CELL_WIDTH, CELL_HEIGHT, TRUE

    ret

MoveChildByCenter endp