Delphi如何实现一个简单计算器界面的设计！

Delphi如何实现一个简单计算器界面的设计！

方法1：上网下载一个控件；
方法2：自己写一个，参考如下
unit Unit1

interface

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

type
TForm1 = class(TForm)
Panel1: TPanel
SpeedButton1: TSpeedButton
SpeedButton2: TSpeedButton
SpeedButton3: TSpeedButton
SpeedButton4: TSpeedButton
SpeedButton5: TSpeedButton
SpeedButton6: TSpeedButton
SpeedButton7: TSpeedButton
SpeedButton8: TSpeedButton
SpeedButton9: TSpeedButton
SpeedButton10: TSpeedButton
SpeedButton11: TSpeedButton
SpeedButton12: TSpeedButton
SpeedButton13: TSpeedButton
SpeedButton14: TSpeedButton
SpeedButton15: TSpeedButton
SpeedButton16: TSpeedButton
Edit1: TEdit
SpeedButton17: TSpeedButton
procedure SpeedButton1Click(Sender: TObject)
procedure SpeedButton12Click(Sender: TObject)
procedure SpeedButton13Click(Sender: TObject)
procedure SpeedButton17Click(Sender: TObject)
procedure FormKeyPress(Sender: TObject var Key: Char)
private
{ Private declarations }
public
{ Public declarations }
end

var
Form1: TForm1

implementation

{$R *.dfm}
var
Flag: Boolean = True //。标记位
Flag1: Integer = 1 //计算方法标志位
num1, num2, result: Real
flagresult: Boolean = False

procedure TForm1.SpeedButton1Click(Sender: TObject)
var
str: string
begin
str := Edit1.Text
if (Length(str) = 1) and (str = 0) then
Edit1.Clear
Edit1.Color := clBlue
if ((Sender as TSpeedButton).Caption = .) then
begin
if Flag then
begin
Edit1.Text := Edit1.Text (sender as TSpeedButton).Caption
Flag := False
end
end
else
Edit1.Text := Edit1.Text (sender as TSpeedButton).Caption
end

procedure TForm1.SpeedButton12Click(Sender: TObject)
begin
Edit1.Color := clRed
num2 := StrToFloatDef(Edit1.Text, 0.00)
case Flag1 of
1: result := num1 num2
2: result := num1 - num2
3: result := num1 * num2
4: if num2 = 0 then
begin
MessageBox(0, 除数为0, , 0)
result := 0
end
else
result := num1 / num2
end
Edit1.Text := FloatToStr(result)
end

procedure TForm1.SpeedButton13Click(Sender: TObject)
begin
Flag1 := (Sender as TSpeedButton).Tag
num1 := StrToFloatDef(Edit1.Text, 0.00)
Edit1.Text := 0
end

procedure TForm1.SpeedButton17Click(Sender: TObject)
begin
Flag := True //。标记位
Flag1 := 1 //计算方法标志位
num1 := 0
num2 := 0
result := 0
Edit1.Text := 0
end

procedure TForm1.FormKeyPress(Sender: TObject var Key: Char)
begin
case key of
1: SpeedButton1.Click
2: SpeedButton2.Click
3: SpeedButton3.Click
4: SpeedButton4.Click
5: SpeedButton5.Click
6: SpeedButton6.Click
7: SpeedButton7.Click
8: SpeedButton8.Click
9: SpeedButton9.Click
0: SpeedButton10.Click
.: SpeedButton11.Click
: SpeedButton13.Click
-: SpeedButton14.Click
*: SpeedButton15.Click
/: SpeedButton16.Click
end
end

end.