刚学Delphi碰到问题
我看的是Delphi 7从入门到精通其中有个例子这样的
unit Unit1;

interface

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

type
TForm1 = class(TForm)
procedure FormMouseDown(Sender: TObject; Button: TMouseButton;
Shift: TShiftState; X, Y: Integer);
private
{ Private declarations }
public
{ Public declarations }
end;

var
Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.FormMouseDown(Sender: TObject; Button: TMouseButton;
Shift: TShiftState; X, Y: Integer);
var
Btn:TButton; 运行后显示这里出错
begin
Btn:=TButton.Create(Self);
Btn.Parent:=Self;
Btn.Left:=X;
Btn.Top:=Y;
Btn.Width:=Btn.Width=50;
Btn.Caption:=Format( 'Button at %d,%d ',[X,Y]);
end;

end.

为什么运行是出错的？我是按书上写的

[解决办法]
uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls;
~~~~~~~~添加

Btn.Width:=Btn.Width=50;
~~~~~~~~~~删去