对话框拖动及其禁止方法

禁止拖动对话框方法：

在WM_HITTEST对应的消息处理函数OnNcHitTest中直接返回TRUE， 或者当指向对话框标题栏时，返回客户区的值HTCLIENT

例子：

UINT CWelcomeDlg::OnNcHitTest(CPoint point)
{
    // TODO: Add your message handler code here and/or call default
   
    return HTCLIENT;
}

拖动对话框方法：

在WM_HITTEST对应的消息处理函数OnNcHitTest中， 当指向对话框客户区时，返回标题区的值HTCAPTION

例子：

UINT CDlg::OnNcHitTest(CPoint point)
{
    // TODO: Add your message handler code here and/or call default
    ScreenToClient(&point);

    if (point.y >= 0 && point.y <= DLGCAPHIGHT)
    {
        return HTCAPTION;
    }
   
    return CDialog::OnNcHitTest(point);
}

参考资料：

WM_NCHITTEST

The WM_NCHITTEST message is sent to a window when the cursor moves, or when a mouse button is pressed or released. If the mouse is not captured, the message is sent to the window beneath the cursor. Otherwise, the message is sent to the window that has captured the mouse.

A window receives this message through its WindowProc function.

LRESULT CALLBACK WindowProc(  HWND hwnd,       // handle to window  UINT uMsg,       // WM_NCHITTEST  WPARAM wParam,   // not used  LPARAM lParam    // horizontal and vertical position);

Parameters

wParam

This parameter is not used.

lParam

The low-order word specifies the x-coordinate of the cursor. The coordinate is relative to the upper-left corner of the screen.

The high-order word specifies the y-coordinate of the cursor. The coordinate is relative to the upper-left corner of the screen.

Return Values

The return value of the DefWindowProc function is one of the following values, indicating the position of the cursor hot spot.

Value	Location of hot spot
HTBORDER	In the border of a window that does not have a sizing border.
HTBOTTOM	In the lower-horizontal border of a resizable window (the user can click the mouse to resize the window vertically).
HTBOTTOMLEFT	In the lower-left corner of a border of a resizable window (the user can click the mouse to resize the window diagonally).
HTBOTTOMRIGHT	In the lower-right corner of a border of a resizable window (the user can click the mouse to resize the window diagonally).
HTCAPTION	In a title bar.
HTCLIENT	In a client area.
HTCLOSE	In a Close button.
HTERROR	On the screen background or on a dividing line between windows (same as HTNOWHERE, except that the DefWindowProc function produces a system beep to indicate an error).
HTGROWBOX	In a size box (same as HTSIZE).
HTHELP	In a Help button.
HTHSCROLL	In a horizontal scroll bar.
HTLEFT	In the left border of a resizable window (the user can click the mouse to resize the window horizontally).
HTMENU	In a menu.
HTMAXBUTTON	In a Maximize button.
HTMINBUTTON	In a Minimize button.
HTNOWHERE	On the screen background or on a dividing line between windows.
HTREDUCE	In a Minimize button.
HTRIGHT	In the right border of a resizable window (the user can click the mouse to resize the window horizontally).
HTSIZE	In a size box (same as HTGROWBOX).
HTSYSMENU	In a window menu or in a Close button in a child window.
HTTOP	In the upper-horizontal border of a window.
HTTOPLEFT	In the upper-left corner of a window border.
HTTOPRIGHT	In the upper-right corner of a window border.
HTTRANSPARENT	In a window currently covered by another window in the same thread (the message will be sent to underlying windows in the same thread until one of them returns a code that is not HTTRANSPARENT).
HTVSCROLL	In the vertical scroll bar.
HTZOOM	In a Maximize button.

 

CWnd::OnNcHitTest 

afx_msg UINT OnNcHitTest( CPoint point );

Return Value

One of the mouse hit-test enumerated values listed below.

Parameters

point

Contains the x- and y-coordinates of the cursor. These coordinates are always screen coordinates.

Remarks

The framework calls this member function for the CWnd object that contains the cursor (or the CWnd object that used the SetCapture member function to capture the mouse input) every time the mouse is moved.

Note   This member function is called by the framework to allow your application to handle a Windows message. The parameters passed to your function reflect the parameters received by the framework when the message was received. If you call the base-class implementation of this function, that implementation will use the parameters originally passed with the message and not the parameters you supply to the function.

See Also   CWnd::GetCapture,WM_NCHITTEST

Mouse Enumerated Values

• HTBORDER   In the border of a window that does not have a sizing border.
  
  
• HTBOTTOM   In the lower horizontal border of the window.
  
  
• HTBOTTOMLEFT   In the lower-left corner of the window border.
  
  
• HTBOTTOMRIGHT   In the lower-right corner of the window border.
  
  
• HTCAPTION   In a title-bar area.
  
  
• HTCLIENT   In a client area.
  
  
• HTERROR   On the screen background or on a dividing line between windows (same as HTNOWHERE except that the DefWndProc Windows function produces a system beep to indicate an error).
  
  
• HTGROWBOX   In a size box.
  
  
• HTHSCROLL   In the horizontal scroll bar.
  
  
• HTLEFT   In the left border of the window.
  
  
• HTMAXBUTTON   In a Maximize button.
  
  
• HTMENU   In a menu area.
  
  
• HTMINBUTTON   In a Minimize button.
  
  
• HTNOWHERE   On the screen background or on a dividing line between windows.
  
  
• HTREDUCE   In a Minimize button.
  
  
• HTRIGHT   In the right border of the window.
  
  
• HTSIZE   In a size box (same as HTGROWBOX).
  
  
• HTSYSMENU   In a Control menu or in a Close button in a child window.
  
  
• HTTOP   In the upper horizontal border of the window.
  
  
• HTTOPLEFT   In the upper-left corner of the window border.
  
  
• HTTOPRIGHT   In the upper-right corner of the window border.
  
  
• HTTRANSPARENT   In a window currently covered by another window.
  
  
• HTVSCROLL   In the vertical scroll bar.
  
  
• HTZOOM   In a Maximize button.