学习官方示例 - System.TClass

本例效果图:

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代码文件:

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unit Unit1;



interface



uses

  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,

  Dialogs, StdCtrls;



type

  TForm1 = class(TForm)

    ListBox1: TListBox;

    Button1: TButton;

    Button2: TButton;

    Button3: TButton;

    procedure Button1Click(Sender: TObject);

    procedure Button2Click(Sender: TObject);

    procedure Button3Click(Sender: TObject);

  end;



var

  Form1: TForm1;



implementation



{$R *.dfm}



{获取 Button1 的父类}

procedure TForm1.Button1Click(Sender: TObject);

var

  ClassRef: TClass;

begin

  ListBox1.Clear;

  ClassRef := Sender.ClassType;

  while ClassRef <> nil do

  begin

    ListBox1.Items.Add(ClassRef.ClassName);

    ClassRef := ClassRef.ClassParent;

  end;

end;



{获取 ListBox1 的父类}

procedure TForm1.Button2Click(Sender: TObject);

var

  ClassRef: TClass;

begin

  ListBox1.Clear;

  ClassRef := ListBox1.ClassType;

  while ClassRef <> nil do

  begin

    ListBox1.Items.Add(ClassRef.ClassName);

    ClassRef := ClassRef.ClassParent;

  end;

end;



{获取当前 Form 的父类}

procedure TForm1.Button3Click(Sender: TObject);

var

  ClassRef: TClass;

begin

  ListBox1.Clear;

  ClassRef := Self.ClassType;

  while ClassRef <> nil do

  begin

    ListBox1.Items.Add(ClassRef.ClassName);

    ClassRef := ClassRef.ClassParent;

  end;

end;



end.


 
   

窗体文件:

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object Form1: TForm1

  Left = 0

  Top = 0

  Caption = 'Form1'

  ClientHeight = 147

  ClientWidth = 282

  Color = clBtnFace

  Font.Charset = DEFAULT_CHARSET

  Font.Color = clWindowText

  Font.Height = -11

  Font.Name = 'Tahoma'

  Font.Style = []

  OldCreateOrder = False

  PixelsPerInch = 96

  TextHeight = 13

  object ListBox1: TListBox

    Left = 0

    Top = 0

    Width = 161

    Height = 147

    Align = alLeft

    ItemHeight = 13

    TabOrder = 0

    ExplicitHeight = 155

  end

  object Button1: TButton

    Left = 184

    Top = 24

    Width = 75

    Height = 25

    Caption = 'Button1'

    TabOrder = 1

    OnClick = Button1Click

  end

  object Button2: TButton

    Left = 184

    Top = 64

    Width = 75

    Height = 25

    Caption = 'Button2'

    TabOrder = 2

    OnClick = Button2Click

  end

  object Button3: TButton

    Left = 184

    Top = 104

    Width = 75

    Height = 25

    Caption = 'Button3'

    TabOrder = 3

    OnClick = Button3Click

  end

end