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;