窗口有关问题

窗口问题
unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, Menus, ToolWin, ComCtrls, ExtCtrls, ImgList,Unit4;

type
  TfrMain = class(TForm)
   
  procedure muNewCompClick(Sender: TObject);
  private
  { Private declarations }
  public
  { Public declarations }
  frMain: TfrMain;
  end;

var
  frMain: TfrMain;
  compBox: TAboutBox2;
implementation

{$R *.dfm}


procedure TfrMain.muNewCompClick(Sender: TObject);
begin
  compBox:=TAboutBox2.Create(Self);
  try
  compBox.ShowModal;
  finally
  compBox.Free;
  end;
end;

end.


------------------------------------------


unit Unit4;

interface

uses Windows, SysUtils, Classes, Graphics, Forms, Controls, StdCtrls,
  Buttons, ExtCtrls,Dialogs, DB, ADODB;

type
  TAboutBox2 = class(TForm)
  Panel1: TPanel;
  OKButton: TButton;
  Label1: TLabel;
  edtCompany: TEdit;
  ADOConnection1: TADOConnection;
  ADOCommand1: TADOCommand;
  procedure OKButtonClick(Sender: TObject);
  procedure FormCreate(Sender: TObject);
  private
  { Private declarations }
  public
  { Public declarations }
  end;

var
  AboutBox2: TAboutBox2;
  txt :string;
  datapath:string;

implementation

{$R *.dfm}

procedure TAboutBox2.OKButtonClick(Sender: TObject);
begin
  txt := edtCompany.Text;
  就是在这里如何把txt传给TfrMain 里面的组建

end;

procedure TAboutBox2.FormCreate(Sender: TObject);
begin
  end;

end.

主窗口创建出子窗口，
子窗口里面的值如何在确定后提供给主窗口呢？

[解决办法]
1.uses unit1;
frMain.caption := edtCompany.Text;

2.楼主的unit1单元没必要定义两个
frMain: TfrMain;

[解决办法]
你的问题貌似是在AboutBox2的事件中直接向TfrMain中传递txt的值吧？
那么AboutBox2中需要uses Unit1,这个uses需要写在implementation下面，这样才能避免相互引用出错