高分超级难题，在软件运行时达到软件设计时的效果，打造自己的开发工具！(300分)

各位高手，在自己编写的软件运行时，也可以看到控件周围的六个小黑框，
并可以拖动，改变大小，请问如何实现？
我只看到窗口有一个Designer属性，还有什么IDesignerHook，DesignWindows.pas等信息，
但是，不知道怎么使用，请各位，各抒己见！

up

我写的一点东西。去看看吧对你有帮助
http://www.delphibbs.com/delphibbs/dispq.asp?lid=1619232

use dream controls

8個點的透明方框原碼如下：
unit DdhSizer;

interface

uses
Classes, Windows, Messages, Controls, StdCtrls;

const
sc_DragMove: Longint = $F012;

type
TDdhSizeButton = class (TButton)
public
procedure WmNcHitTest (var Msg: TWmNcHitTest);
message wm_NcHitTest;
end;

TDdhSizerControl = class (TCustomControl)
private
FControl: TControl;
FRectList: array [1..8] of TRect;
FPosList: array [1..8] of Integer;
public
constructor Create (AOwner: TComponent;
AControl: TControl);
procedure CreateParams (var Params: TCreateParams);
override;
procedure CreateHandle
override;
procedure WmNcHitTest (var Msg: TWmNcHitTest)
message wm_NcHitTest;
procedure WmSize (var Msg: TWmSize)
message wm_Size;
procedure WmLButtonDown (var Msg: TWmLButtonDown)
message wm_LButtonDown;
procedure WmMove (var Msg: TWmMove)
message wm_Move;
procedure WmKeyDown(var Msg: TWMKEY)
message WM_KEYDOWN;
procedure Paint
override;
procedure SizerControlExit (Sender: TObject);
end;

procedure Register;

implementation

uses
Graphics;

// TDdhSizeButton methods

procedure TDdhSizeButton.WmNcHitTest(var Msg: TWmNcHitTest);
var
Pt: TPoint;
begin
Pt := Point (Msg.XPos, Msg.YPos);
Pt := ScreenToClient (Pt);
if (Pt.x < 5) and (pt.y < 5) then
Msg.Result := htTopLeft
else if (Pt.x > Width - 5) and (pt.y < 5) then
Msg.Result := htTopRight
else if (Pt.x > Width - 5) and (pt.y > Height - 5) then
Msg.Result := htBottomRight
else if (Pt.x < 5) and (pt.y > Height - 5) then
Msg.Result := htBottomLeft
else if (Pt.x < 5) then
Msg.Result := htLeft
else if (pt.y < 5) then
Msg.Result := htTop
else if (Pt.x > Width - 5) then
Msg.Result := htRight
else if (pt.y > Height - 5) then
Msg.Result := htBottom
else
inherited;
end;

// TDdhSizerControl methods

constructor TDdhSizerControl.Create (
AOwner: TComponent
AControl: TControl);
var
R: TRect;
begin
inherited Create (AOwner);
FControl := AControl;
// install the new handler
OnExit := SizerControlExit;
// set the size and position
R := FControl.BoundsRect;
InflateRect (R, 2, 2);
BoundsRect := R;
// set the parent
Parent := FControl.Parent;
// create the list of positions
FPosList [1] := htTopLeft;
FPosList [2] := htTop;
FPosList [3] := htTopRight;
FPosList [4] := htRight;
FPosList [5] := htBottomRight;
FPosList [6] := htBottom;
FPosList [7] := htBottomLeft;
FPosList [8] := htLeft;
end;

procedure TDdhSizerControl.CreateHandle;
begin
inherited CreateHandle;
SetFocus;
end;

procedure TDdhSizerControl.CreateParams (var Params: TCreateParams);
begin
inherited CreateParams(Params);
Params.ExStyle := Params.ExStyle +
ws_ex_Transparent;
end;

procedure TDdhSizerControl.Paint;
var
I: Integer;
begin
Canvas.Brush.Color := clBlack;
for I := 1 to 8 do
Canvas.Rectangle (FRectList .Left, FRectList .Top,
FRectList .Right, FRectList .Bottom);
end;

procedure TDdhSizerControl.WmNcHitTest(var Msg: TWmNcHitTest);
var
Pt: TPoint;
I: Integer;
begin
Pt := Point (Msg.XPos, Msg.YPos);
Pt := ScreenToClient (Pt);
Msg.Result := 0;
for I := 1 to 8 do
if PtInRect (FRectList , Pt) then
Msg.Result := FPosList ;
// if the return value was not set
if Msg.Result = 0 then
inherited;
end;

procedure TDdhSizerControl.WmSize (var Msg: TWmSize);
var
R: TRect;
begin
R := BoundsRect;
InflateRect (R, -2, -2);
FControl.BoundsRect := R;
// setup data structures
FRectList [1] := Rect (0, 0, 5, 5);
FRectList [2] := Rect (Width div 2 - 3, 0,
Width div 2 + 2, 5);
FRectList [3] := Rect (Width - 5, 0, Width, 5);
FRectList [4] := Rect (Width - 5, Height div 2 - 3,
Width, Height div 2 + 2);
FRectList [5] := Rect (Width - 5, Height - 5,
Width, Height);
FRectList [6] := Rect (Width div 2 - 3, Height - 5,
Width div 2 + 2, Height);
FRectList [7] := Rect (0, Height - 5, 5, Height);
FRectList [8] := Rect (0, Height div 2 - 3,
5, Height div 2 + 2);
end;

procedure TDdhSizerControl.SizerControlExit (Sender: TObject);
begin
Free;
end;

procedure TDdhSizerControl.WmLButtonDown (var Msg: TWmLButtonDown);
begin
Perform (wm_SysCommand, sc_DragMove, 0);
end;

procedure TDdhSizerControl.WmMove (var Msg: TWmMove);
var
R: TRect;
begin
R := BoundsRect;
InflateRect (R, -2, -2);
FControl.Invalidate
// repaint entire surface
FControl.BoundsRect := R;
end;

procedure TDdhSizerControl.WmKeyDown(var Msg: TWMKEY);
begin
if (Msg.CharCode = VK_DELETE) then
begin
FControl.Free;
Free;
end;
end;

// components registration

procedure Register;
begin
RegisterComponents ('DDHB', [TDdhSizeButton]);
RegisterNoIcon ([TDdhSizerControl]);
end;

end.



在被托動控件的OnClick事件中寫：
TDdhSizerControl.Create(self, Sender as TControl);

谢谢leway，我采纳了你的方案，wr960204的也不错！