子窗口（fsMDIChild）怎样隐藏其它窗口

Question

我是delphi新手，求详解和代码
我的登录界面为子窗口（fsMDIChild），但是我想在我程序运行时，把主窗口（fsMDIFrom）和其它子窗口隐藏了，登录后再显示主窗口。我已将所有窗口的Visible属性改为False，没用。

Answer 1

procedure TFm_Login.FormCreate(Sender: TObject);
begin
  Fm_login.Visible := True;
  Fm_main.Visible := False;
  Application.ShowMainForm := False;
  cobUserName.Clear;
  with Dm_base.tbUser do
  begin
    First;
    while not Eof do
    begin
      cobUserName.Items.Add(FieldByName('UserName').AsString);
      Next;
    end;
  end;  
end;procedure TFm_Login.BitBtn1Click(Sender: TObject);
var
  cBaseRight,
  cRight,
  cUserPass,
  cUserId,
  cUserName:String;  bIsAdmin:Boolean;  iMenuItemCnt:Integer;
begin
  //判断登录的用户.
  cUserName:=Trim(cobUserName.Text);
  if cUserName='' then Begin
    ShowMsg('用户名称不为空!',0);
    cobUserName.SetFocus;
    Abort;
  End;  with dm_base.tbUser do begin
    if not Locate('UserName',cUserName,[]) then
    begin
      ShowMsg('用户名称不存在!',0);
      cobUserName.SetFocus;
      Abort;
    end
    else begin  //取用户名及密码!
      cUserId   :=FieldbyName('UserNo').AsString;
      cUserName :=FieldbyName('UserName').AsString;
      cUserPass :=FieldbyName('UserPass').AsString;      if FieldbyName('IsAdmin').AsString='Y' then
        P_IsNotAdmin:=True
      Else
        P_IsNotAdmin:=False;
    End;    if Edit1.text<>cUserPass then begin
      ShowMsg('用户密码错,请重新输入!',0);
      Edit1.SetFocus;
      Exit;
    end;
  end;  Fm_main.StatusBar1.Panels[2].text:=' '+cUserId;
  Fm_main.StatusBar1.Panels[3].Text:=cUserName;
  Fm_main.StatusBar1.Panels[5].text:=' '+Formatdatetime('YYYY"年"MM"月"DD"日"',Date);  P_UserNo  :=cUserId;
  P_UserName:=cUserName;  Fm_main.Visible:=True;
  Fm_main.Enabled:=True;  Application.ShowMainForm:=True;

Answer 2

登录界面的代码就不用写了
我将Fm_main.Visible := False;
  Application.ShowMainForm := False;
这两句写了后运行程序，但是Frm_Login未显示出来啊

Answer 3

工程文件代码，我这里面有个logo窗体，你可以去掉var
  hMutex:HWND;
  Ret:Integer;
  hWinHwd:HWND;
  UserName:array[0..20] of char;
  fLength:dword;
  
begin
  Application.Initialize;
  Application.Initialize;
  Application.Title:='CheckPrint.exe';
  hWinHwd:=FindWindow(nil,Pchar('CheckPrint'));
  SetForeGroundWindow(hWinHwd);
  ShowWindow(hWinHwd,SW_SHOW);
  Application.Title := '票据打印系统';
  hMutex:=CREATEMUTEX( nil,TRUE, Pchar('CheckPrint'));
  Ret:=GetLastError();
  if Ret<>ERROR_ALREADY_EXISTS then
  Begin
    Fm_Logo:=TFm_Logo.Create(Application);
    Fm_Logo.Show;
    Fm_Logo.Update;
    Application.CreateForm(TDm_Base, Dm_Base);
    Application.CreateForm(Tfm_main, fm_main);
    fLength:=20;
    GetUserName(UserName,fLength);
    if GetEnumValue(TypeInfo(TDesignUser),UpperCase(UserName))<>-1 then
    begin
      P_UserNo  :='Admin';
      P_UserName:='Admin';
      P_IsNotAdmin:=True;
    end
    else
      Application.CreateForm(TFm_Login, Fm_Login);
    Fm_logo.Hide;
    Fm_logo.Close;
    Application.Run;
  End;
  ReleaseMutex(hMutex);
end.