目的：今天工作的主要内容是开发一个带提示灯的按钮
思路整理：
1.找到父类Tbutton
2.继承该父类，在父类的create事件中创建edit控件
3.当按钮单击事件发生时，edit控件变为绿色，以实现提示灯的作用
代码实现：
首先实现在窗体中创建自己定义的类（TMybutton）
代码如下
View Code
unit Unit1;
interface
uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls;
type
TForm1 = class(TForm)
btn1: TButton;
procedure btn1Click(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;
TMyButton = class(TButton)
private
{ private declarations }
protected
{ protected declarations }
public
{ public declarations }
published
{ published declarations }
end;
var
Form1: TForm1;
implementation
{$R *.dfm}
procedure TForm1.btn1Click(Sender: TObject);
begin
with TMyButton.Create(self) do
begin
parent := self;
Left := Random(self.ClientWidth - Width);
Top := Random(self.ClientHeight - Height);
end;
end;
end.
下面我们开始对继承的这个类进行改造
代码如下
unit Unit1;
interface
uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls;
type
TForm1 = class(TForm)
btn1: TButton;
procedure btn1Click(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;
TMyButton = class(TButton)
private
{ private declarations }
protected
{ protected declarations }
public
{ public declarations }
constructor Create(AOwner: TComponent); override;
destructor Destroy; override;
procedure Click; override;
published
{ published declarations }
end;
var
Form1: TForm1;
implementation
{$R *.dfm}
procedure TForm1.btn1Click(Sender: TObject);
begin
with TMyButton.Create(self) do
begin
parent := self;
left := Random(self.Width - Width);
top := Random(self.Height - Height);
end;
end;
{ TMyButton }
procedure TMyButton.Click;
begin
inherited;
if TEdit(self.Components[0]).Brush.Color = clWhite then
begin
TEdit(self.Components[0]).Brush.Color := clGreen;
exit;
end;
if TEdit(self.Components[0]).Brush.Color = clGreen then
begin
TEdit(self.Components[0]).Brush.Color := clWhite;
exit;
end;
end;
constructor TMyButton.Create(AOwner: TComponent);
begin
inherited;
self.Height := 50;
self.Width := 50;
with TEdit.Create(self) do
begin
parent := self;
Height := self.Height div 2 - 35;
Width := 10;
left := self.Width div 2 - 5;
top := self.Height div 2;
Enabled := False;
Brush.Color := clWhite;
end;
end;
destructor TMyButton.Destroy;
begin
inherited;
end;
end.
这样我们通过类的继承的手段，实现了一个带指示灯的按钮功能，希望对读者有所帮助
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