mainfrm.pas

《Delphi开发人员指南》配书原码

unit MainFrm;

interface

uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
  StdCtrls;

type
  TMainForm = class(TForm)
    lbSamps: TListBox;
    memInfo: TMemo;
    procedure FormCreate(Sender: TObject);
    procedure lbSampsClick(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  MainForm: TMainForm;

implementation
uses TypInfo;

{$R *.DFM}


procedure TMainForm.FormCreate(Sender: TObject);
begin
  with lbSamps.Items do
  begin
    AddObject('Word', TypeInfo(Word));
    AddObject('Integer', TypeInfo(Integer));
    AddObject('Byte', TypeInfo(Byte));
  end;
end;

procedure TMainForm.lbSampsClick(Sender: TObject);
var
  OrdTypeInfo: PTypeInfo;
  OrdTypeData: PTypeData;

  TypeNameStr: String;
  TypeKindStr: String;
  MinVal, MaxVal: Integer;
begin
  memInfo.Lines.Clear;
  with lbSamps do
  begin

    // Get the TTypeInfo pointer
    OrdTypeInfo := PTypeInfo(Items.Objects[ItemIndex]);
    // Get the TTypeData pointer
    OrdTypeData := GetTypeData(OrdTypeInfo);

    // Get the type name string
    TypeNameStr := OrdTypeInfo.Name;
    // Get the type kind string
    TypeKindStr := GetEnumName(TypeInfo(TTypeKind), Integer(OrdTypeInfo^.Kind));

    // Get the minimum and maximum values for the type
    MinVal := OrdTypeData^.MinValue;
    MaxVal := OrdTypeData^.MaxValue;


    // Add the information to the memo
    with memInfo.Lines do
    begin
      Add('Type Name: '+TypeNameStr);
      Add('Type Kind: '+TypeKindStr);

      Add('Min Val: '+IntToStr(MinVal));
      Add('Max Val: '+IntToStr(MaxVal));
    end;
  end;
end;

end.