Delphi標准控件-單選按鈕和復選框

單選按鈕（RadioButton）和復選按框（CheckBox）都是很常用的組件，尤其是在對話框中。單選按鈕（RadioButton）是一種具有排他性的選擇組件，用戶每一次只能選擇其中的一個（在同一個容器組件中，如同一Form上或RadioBox中）。而復選框（CheckBox）則不同，可以同時選擇多個。

兩種組件都有一個Checked屬性，用於標識和檢測是否被選中。我們使用這兩個組件，給上一節（Memo組件介紹）的例程（簡單編輯器）添加一些新的功能，使它可以選擇字體顏色和字體的樣式。

程序的界面如下圖所示：

程序如下：

unit Unit1; interface uses Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs, StdCtrls; type TForm1 = class(TForm) Memo1: TMemo; Button1: TButton; SaveDialog1: TSaveDialog; OpenDialog1: TOpenDialog; Button2: TButton; Button3: TButton; Button4: TButton; Button5: TButton; Button6: TButton; Button7: TButton; RadioButton1: TRadioButton; RadioButton2: TRadioButton; RadioButton3: TRadioButton; CheckBox1: TCheckBox; CheckBox2: TCheckBox; CheckBox3: TCheckBox; procedure Button1Click(Sender: TObject); procedure FormCreate(Sender: TObject); procedure Button2Click(Sender: TObject); procedure Button5Click(Sender: TObject); procedure Button6Click(Sender: TObject); procedure Button3Click(Sender: TObject); procedure Button4Click(Sender: TObject); procedure Button7Click(Sender: TObject); procedure RadioButton1Click(Sender: TObject); procedure RadioButton2Click(Sender: TObject); procedure RadioButton3Click(Sender: TObject); procedure CheckBox1Click(Sender: TObject); procedure CheckBox2Click(Sender: TObject); procedure CheckBox3Click(Sender: TObject); private { Private declarations } public { Public declarations } end; var Form1: TForm1; implementation {$R *.DFM} procedure TForm1.Button1Click(Sender: TObject); begin memo1.Lines.Add('在末端添加文本'); end; procedure TForm1.FormCreate(Sender: TObject); begin memo1.Lines.Text:='這裡是Memo組件示例'; memo1.Font.Color:=clRed; //設定文本的初始顏色為紅色，因為RadioButton1是默認選中的 end; procedure TForm1.Button2Click(Sender: TObject); begin if Memo1.SelLength>0 then Memo1.CutToClipboard; end; procedure TForm1.Button5Click(Sender: TObject); begin if savedialog1.Execute then memo1.Lines.SaveToFile(savedialog1.FileName); end; procedure TForm1.Button6Click(Sender: TObject); begin if Opendialog1.Execute then memo1.Lines.LoadFromFile(opendialog1.FileName); end; procedure TForm1.Button3Click(Sender: TObject); begin if Memo1.SelLength>0 then Memo1.CopyToClipboard; end; procedure TForm1.Button4Click(Sender: TObject); begin if Memo1.SelLength=0 then Memo1.PasteFromClipboard; end; procedure TForm1.Button7Click(Sender: TObject); begin close; end; procedure TForm1.RadioButton1Click(Sender: TObject); begin if radiobutton1.Checked=true then //判斷是否被選中 Memo1.Font.color:=clRed; //改變顏色 end; procedure TForm1.RadioButton2Click(Sender: TObject); begin if radiobutton2.Checked=true then Memo1.Font.Color:=clBlue; end; procedure TForm1.RadioButton3Click(Sender: TObject); begin if radiobutton3.Checked=true then Memo1.Font.Color:=clGreen; end; procedure TForm1.CheckBox1Click(Sender: TObject); begin if checkbox1.Checked=true then Memo1.Font.Style:=Memo1.Font.Style+[fsBold] else Memo1.Font.Style:=Memo1.Font.Style-[fsBold]; end; procedure TForm1.CheckBox2Click(Sender: TObject); begin if checkbox2.Checked=true then Memo1.Font.Style:=Memo1.Font.Style+[fsItalic] else Memo1.Font.Style:=Memo1.Font.Style-[fsItalic]; end; procedure TForm1.CheckBox3Click(Sender: TObject); begin if checkbox3.Checked=true then Memo1.Font.Style:=Memo1.Font.Style+[fsUnderline] else Memo1.Font.Style:=Memo1.Font.Style-[fsUnderline]; end; end.