Question

delphi，关于登陆界面和主界面的显示问题。请高手指教。

要求点击主界面上的按钮，就回显示登陆窗口，然后输入用户名和密码，就可以进入相应的模块，我的代码没错误，就是不能运行显示。下面是代码。
这是登陆界面的代码：
var
flogin: Tflogin;
Flag: Boolean;
implementation
uses datam,frmmain;
{$R *.dfm}
procedure Tflogin.ButtoncancleClick(Sender: TObject);
begin
Flag:=False;
Close;
end;
procedure Tflogin.ButtonenterClick(Sender: TObject);
begin
try
with Data do
begin
ADOQlogin.Close;
ADOQlogin.SQL.Clear;
ADOQlogin.SQL.Add('select * from users where YHM="'+Editname.Text+'"');
ADOClogin.Connected:=True;
ADOQlogin.Open;
end
except
begin
MessageDlg('Connect to Database Error!',mtError,[mbOK],0);
close;
end
end;
if Data.ADOQlogin.RecordCount=1 then
if Data.AdoQlogin['MM']=Editpass.Text then
begin
Flag:=True;
end
else begin
Flag:=False;
MessageDlg('Password Error!',mtError,[mbOK],0);
end
else begin
Flag:=False;
MessageDlg('Uesrname Error!',mtError,[mbOK],0);
end;
close;
end;
procedure Tflogin.FormCloseQuery(Sender: TObject; var CanClose: Boolean);
begin
if not Flag then begin
Data.ADOQlogin.Close;
Data.ADOClogin.Connected:=False;
end
end;
end.
这是主界面的代码：
var
fmain: Tfmain;

implementation
uses datam,menzhenguanli,zhuyuanguanli,yaopinguanli,xitongweihu,DLCK;
{$R *.dfm}

procedure Tfmain.ButtonmenzhenClick(Sender: TObject);
begin
flogin.ShowModal; {显示登录窗体}
if Data.ADOClogin.Connected then
if (Data.ADOQlogin['YHQX']=1) or
(Data.ADOQlogin['YHQX']=10) then begin
Data.ADOQlogin.Edit;
Data.ADOQlogin['DLSJ']:=Now;
Data.ADOQlogin.Post;
Application.CreateForm(Tfrmmenzhen; frmmenzhen); flogin.Hide;
fmain.Hide;
frmmenzhen.ShowModal;
end
else
MessageDlg('you not have Authorization!',mtError,[mbOK],0);
end;

procedure Tfmain.ButtontuichuClick(Sender: TObject);
begin
Application.Terminate;
end;
procedure Tfmain.ButtonzhuyuanClick(Sender: TObject);
begin
flogin.ShowModal;
if Data.ADOClogin.Connected then
if (Data.ADOQlogin['YHQX']=2) or
(Data.ADOQlogin['YHQX']=10) then begin
Data.ADOQlogin.Edit;
Data.ADOQlogin['DLSJ']:=Now;
Data.ADOQlogin.Post;
Application.CreateForm(Tfrmmenzhen; frmmenzhen);
flogin.Hide;
fmain.Hide;
frmmenzhen.ShowModal;
end
else
MessageDlg('you not have Authorization!',mtError,[mbOK],0);
end;
procedure Tfmain.ButtonyaopinClick(Sender: TObject);
begin
flogin.ShowModal;
if Data.ADOClogin.Connected then
if (Data.ADOQlogin['YHQX']=3) or
(Data.ADOQlogin['YHQX']=10) then begin
Data.ADOQlogin.Edit;
Data.ADOQlogin['DLSJ']:=Now;
Data.ADOQlogin.Post;
Application.CreateForm(Tfrmyaopin; frmyaopin);
flogin.Hide;
fmain.Hide;
frmyaopin.ShowModal;
end
else
MessageDlg('you not have Authorization!',mtError,[mbOK],0);
end;
end.

Answer 1

...
if ADOQuery1.RecordCount>0 then
begin
czy:=ADOQuery1.FieldByName('username').Value;
s:=true;
close;
mainform.show;//在这里加入对主窗体的调用就可以了
end
else
if m<3 then
...