搞不懂,按下button为何没有反应?

[zzt71510]

....
type
TForm1 = class(TForm)
Button1: TButton;
procedure Button1Click(Sender: TObject);
procedure scChange(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;

var
Form1: TForm1;
sc:TScrollBar;
implementation

{$R *.dfm}

procedure TForm1.Button1Click(Sender: TObject);
begin
sc:=TScrollBar.Create(self);
sc.Position:=sc.Position+1;
end; //第一部分

procedure TForm1.scChange(Sender: TObject);
begin
showmessage('hhh');
end; //第二部分

end.

搞不懂,按下button为何没有反应?
"procedure TForm1.scChange(Sender: TObject);" 有错吗?

[edgethinking]

这样就有反应了：
-----------------------------------------
unit Unit1;

interface

uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls;

type
TForm1 = class(TForm)
sc: TScrollBar;
Button1: TButton;
procedure Button1Click(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;

var
Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.Button1Click(Sender: TObject);
begin
sc.Position := sc.Position + 1;
end;

end.

[edgethinking]

这样也可以：
--------------------------

unit Unit1;

interface

uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls;

type
TForm1 = class(TForm)
Button1: TButton;
Button2: TButton;
procedure Button1Click(Sender: TObject);
procedure Button2Click(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;

var
Form1: TForm1;
sc:TScrollBar;

implementation

{$R *.dfm}

procedure TForm1.Button1Click(Sender: TObject);
begin
sc := TScrollBar.Create(Self);
sc.Parent := form1;
end;

procedure TForm1.Button2Click(Sender: TObject);
begin
sc.Position := sc.Position + 1;
end;

end.

[liufuyahong]

将Buttton1的click事件改为如下
procedure TForm1.Button1Click(Sender: TObject);
begin
Sc:=TScrollBar.Create(nil);
Sc.OnChange:=ScScroll;
sc.Position:=sc.Position+1;
end; //第一部分

[edgethinking]

楼上的，你有没有调试过呀！

他是少了一句 sc.Parent := from1;
sc没有父窗口的支撑，sc在哪都不知道。

[aiirii]

你的代碼有好几個地方有問題,具體修改如下:

procedure TForm1.Button1Click(Sender: TObject);
begin
sc:=TScrollBar.Create(Self);
sc.Parent := Self;
sc.OnChange := scChange;
sc.Position:=sc.Position+1;
end; //第一部分

procedure TForm1.scChange(Sender: TObject);
begin
showmessage('hhh');
end; //第二部分

end.

[zzt71510]

谢谢大家!