Delphi标准控件-单选按钮和复选框


单选按钮（RadioButton）和复选按框（CheckBox）都是很常用的组件，尤其是在对话框中。单选按钮（RadioButton）是一种具有排他性的选择组件，用户每一次只能选择其中的一个（在同一个容器组件中，如同一Form上或RadioBox中）。而复选框（CheckBox）则不同，可以同时选择多个。
两种组件都有一个Checked属性，用于标识和检测是否被选中。我们使用这两个组件，给上一节（Memo组件介绍）的例程（简单编辑器）添加一些新的功能，使它可以选择字体颜色和字体的样式。
程序的界面如下图所示：
程序如下：
unit Unit1;interfaceusesWindows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,StdCtrls;typeTForm1 = 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;varForm1: TForm1;implementation{$R *.DFM}procedure TForm1.Button1Click(Sender: TObject);beginmemo1.Lines.Add('在末端添加文本');end;procedure TForm1.FormCreate(Sender: TObject);beginmemo1.Lines.Text:='这里是Memo组件示例';memo1.Font.Color:=clRed;//设定文本的初始颜色为红色，因为RadioButton1是默认选中的end;procedure TForm1.Button2Click(Sender: TObject);beginif Memo1.SelLength>0 thenMemo1.CutToClipboard;end;procedure TForm1.Button5Click(Sender: TObject);beginif savedialog1.Execute thenmemo1.Lines.SaveToFile(savedialog1.FileName);end;procedure TForm1.Button6Click(Sender: TObject);beginif Opendialog1.Execute thenmemo1.Lines.LoadFromFile(opendialog1.FileName);end;procedure TForm1.Button3Click(Sender: TObject);beginif Memo1.SelLength>0 thenMemo1.CopyToClipboard;end;procedure TForm1.Button4Click(Sender: TObject);beginif Memo1.SelLength=0 thenMemo1.PasteFromClipboard;end;procedure TForm1.Button7Click(Sender: TObject);beginclose;end;procedure TForm1.RadioButton1Click(Sender: TObject);beginif radiobutton1.Checked=true then      //判断是否被选中Memo1.Font.color:=clRed;                //改变颜色end;procedure TForm1.RadioButton2Click(Sender: TObject);beginif radiobutton2.Checked=true thenMemo1.Font.Color:=clBlue;end;procedure TForm1.RadioButton3Click(Sender: TObject);beginif radiobutton3.Checked=true thenMemo1.Font.Color:=clGreen;end;procedure TForm1.CheckBox1Click(Sender: TObject);beginif checkbox1.Checked=true thenMemo1.Font.Style:=Memo1.Font.Style+[fsBold]elseMemo1.Font.Style:=Memo1.Font.Style-[fsBold];end;procedure TForm1.CheckBox2Click(Sender: TObject);beginif checkbox2.Checked=true thenMemo1.Font.Style:=Memo1.Font.Style+[fsItalic]elseMemo1.Font.Style:=Memo1.Font.Style-[fsItalic];end;procedure TForm1.CheckBox3Click(Sender: TObject);beginif checkbox3.Checked=true thenMemo1.Font.Style:=Memo1.Font.Style+[fsUnderline]elseMemo1.Font.Style:=Memo1.Font.Style-[fsUnderline];end;end.
 
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