Автор: Xavier Pacheco

unit MainFrm;

interface

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

type
  TMainForm = class(TForm)
    Button1: TButton;
    Button2: TButton;
    Button3: TButton;
    Button4: TButton;
    Panel1: TPanel;
    Button5: TButton;
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
    procedure Button3Click(Sender: TObject);
    procedure Button4Click(Sender: TObject);
    procedure Panel1Click(Sender: TObject);
    procedure Button5Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  MainForm: TMainForm;

implementation
uses TypInfo;
{$R *.DFM}

procedure SetIntegerPropertyIfExists(AComp: TComponent; APropName: string;
  AValue: Integer);
var
  PropInfo: PPropInfo;
begin
  PropInfo := GetPropInfo(AComp.ClassInfo, APropName);
  if PropInfo <> nil then
  begin
    if PropInfo^.PropType^.Kind = tkInteger then
      SetOrdProp(AComp, PropInfo, AValue);
  end;
end;

procedure SetObjectPropertyIfExists(AComponent: TComponent; APropName: string;
  AValue: TObject);
var
  PropInfo: PPropInfo;
begin
  PropInfo := GetPropInfo(AComponent.ClassInfo, APropName);
  if PropInfo <> nil then
  begin
    if PropInfo^.PropType^.Kind = tkClass then
      SetObjectProp(AComponent, PropInfo, AValue);
  end;
end;

procedure SetBooleanPropertyIfExists(AComp: TComponent; APropName: string;
  AValue: Boolean);
var
  PropInfo: PPropInfo;
begin
  PropInfo := GetPropInfo(AComp.ClassInfo, APropName);
  if PropInfo <> nil then
  begin
    if PropInfo^.PropType^.Kind = tkEnumeration then
      SetOrdProp(AComp, PropInfo, Integer(AValue));
  end;
end;

procedure SetStringPropertyIfExists(AComp: TComponent; APropName: string;
  AValue: string);
var
  PropInfo: PPropInfo;
  TK: TTypeKind;
begin
  PropInfo := GetPropInfo(AComp.ClassInfo, APropName);
  if PropInfo <> nil then
  begin
    TK := PropInfo^.PropType^.Kind;
    if (TK = tkString) or (TK = tkLString) or (TK = tkWString) then
      SetStrProp(AComp, PropInfo, AValue);
  end;
end;

procedure SetMethodPropertyIfExists(AComp: TComponent; APropName: string;
  AMethod: TMethod);
var
  PropInfo: PPropInfo;
begin
  PropInfo := GetPropInfo(AComp.ClassInfo, APropName);
  if PropInfo <> nil then
  begin
    if PropInfo^.PropType^.Kind = tkMethod then
      SetMethodProp(AComp, PropInfo, AMethod);
  end;
end;

procedure TMainForm.Button1Click(Sender: TObject);
begin
  SetStringPropertyIfExists(Button1, 'Caption', 'Yahoo');
end;

procedure TMainForm.Button2Click(Sender: TObject);
begin
  SetIntegerPropertyIfExists(Button2, 'Width', 50);
end;

procedure TMainForm.Button3Click(Sender: TObject);
begin
  SetBooleanPropertyIfExists(Button3, 'Enabled', False);
end;

procedure TMainForm.Button4Click(Sender: TObject);
var
  F: TFont;
begin
  F := TFont.Create;
  F.Name := 'Arial';
  F.Size := 24;
  F.Color := clRed;
  SetObjectPropertyIfExists(Panel1, 'Font', F);
end;

procedure TMainForm.Button5Click(Sender: TObject);
begin
  SetMethodPropertyIfExists(Button5, 'OnClick',
    GetMethodProp(Panel1, 'OnClick'));
end;

procedure TMainForm.Panel1Click(Sender: TObject);
begin
  ShowMessage(Button5.Caption);
end;

end.