一窗口却换不到另一个窗口中，不报错，

Question

unit z_login;interfaceuses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls;type
  Tf_login = class(TForm)
    Edit1: TEdit;
    edit2: TEdit;
    Button1: TButton;
    Button2: TButton;
    Label1: TLabel;
    Label2: TLabel;
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;var
  f_login: Tf_login;implementation
uses z_data,z_main;{$R *.dfm}procedure Tf_login.Button1Click(Sender: TObject);
begin
if edit1.Text='' then
      application.MessageBox('请输入用户名','提示',64)
  else
    if edit2.Text='' then
      application.MessageBox('请输入密码','提示',64)
       else         with Data1.q_login do
           begin
             close;
             sql.Clear;
             sql.Add('select * from t_user where user_no = :a and passwd = :b');
             parameters.ParamByName('a').Value:=trim(edit1.Text);
             parameters.ParamByName('b').Value:=trim(edit2.Text);
             open;
           end;
        if Data1.q_login.RecordCount>0 then
            begin
               application.MessageBox('用户名或密码错误，请重新输入！','提示',64);
               edit1.Clear;
               edit2.Clear;
               edit1.SetFocus;
             end;end;procedure Tf_login.Button2Click(Sender: TObject);
begin
Application.Terminate;
end;
end.

Answer 1

1. 里面好像没写换哪个窗口.
2. 当Data1.q_login.RecordCount = 0 时才报为用户名或密码错误

Answer 2

我这个登录窗口是从z_main主窗口中
procedure Tf_main.FormShow(Sender: TObject);
begin
application.CreateForm(Tf_login,f_login);
f_login.ShowModal;
f_login.free;
end;
这样新建出来的

Answer 3

当查询成功后close登录框就OK了

Answer 4

if Data1.q_login.RecordCount>0 then
            begin
               application.MessageBox('用户名或密码错误，请重新输入！','提示',64);
               edit1.Clear;
               edit2.Clear;
               edit1.SetFocus;
             end;Data1.q_login.RecordCount>0应该是查询成功吧
查询成功还用重新输入密码和用户名吗？      if Data1.q_login.RecordCount>0 then
            begin
             f_login.close;
            end;