Delphi 实现无窗口移动（发WM_NCHITTEST消息计算，然后再发WM_SYSCOMMAND消息，带参数SC_DRAGMOVE）

procedure imgListMouseDown(Sender: TObject; Button: TMouseButton; Shift: TShiftState; X, Y: Integer);
private
 procedure WMNCHITTEST(var Msg: TWMNCHITTEST); message WM_NCHITTEST;

procedure TfrmStartHit.WMNCHITTEST(var Msg: TWMNCHITTEST);
const
  cOffset = ;
var
  vPoint: TPoint;
begin
  inherited;
  vPoint := ScreenToClient(Point(Msg.XPos, Msg.YPos));
  if PtInRect(Rect(, , cOffset, cOffset), vPoint) then
    Msg.Result := HTTOPLEFT
  else if PtInRect(Rect(Width - cOffset, Height - cOffset, Width, Height), vPoint) then
    Msg.Result := HTBOTTOMRIGHT
  else if PtInRect(Rect(Width - cOffset, , Width, cOffset), vPoint) then
    Msg.Result := HTTOPRIGHT
  else if PtInRect(Rect(, Height - cOffset, cOffset, Height), vPoint) then
    Msg.Result := HTBOTTOMLEFT
  else if PtInRect(Rect(cOffset, , Width - cOffset, cOffset), vPoint) then
    Msg.Result := HTTOP
  else if PtInRect(Rect(, cOffset, cOffset, Height - cOffset), vPoint) then
    Msg.Result := HTLEFT
  else if PtInRect(Rect(Width - cOffset, cOffset, Width, Height - cOffset), vPoint) then
    Msg.Result := HTRIGHT
  else if PtInRect(Rect(cOffset, Height - cOffset, Width - cOffset, Height), vPoint) then
    Msg.Result := HTBOTTOM;
end;

procedure TfrmStartHit.imgListMouseDown(Sender: TObject;
  Button: TMouseButton; Shift: TShiftState; X, Y: Integer);
const
  SC_DRAGMOVE = $F012;
begin
  if (Button = mbLeft) then
  begin
    ReleaseCapture;
    (Self as TControl).Perform(WM_SYSCOMMAND, SC_DRAGMOVE, );
  end;
end;

http://blog.csdn.net/yanjiaye520/article/details/6736069