Question

delphi 7：undeclared identifier

unit Unit1;

interface

uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, Menus,Inifiles, DB, ADODB, DBTables, ComCtrls;

type
Tmainform = class(TForm)
MainMenu1: TMainMenu;
N1: TMenuItem;
N2: TMenuItem;
N3: TMenuItem;
ADOConnection1: TADOConnection;
StatusBar1: TStatusBar;
N4: TMenuItem;
N5: TMenuItem;
N6: TMenuItem;
N7: TMenuItem;
N8: TMenuItem;
N9: TMenuItem;
procedure FormCreat(Sender: TObject);
procedure N9Click(Sender: TObject);
procedure N4Click(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;

var

mainform: Tmainform;
vlogin:string;
vloginname:string;
Vloginstatus:string;
myinifile:Tinifile;
f_student:Tf_student; ////错误行 /////////////////

implementation

uses Unit2; /////错误行///////////
{$R *.dfm}

procedure Tmainform.FormCreat(Sender: TObject);

var
filename:string;

begin
filename:=ExtractFilePath(paramstr(0))+'dblink.ini';
myinifile:=Tinifile.create(filename);
try
adoconnection1.Connected:=false;
adoconnection1.LoginPrompt:= False;
adoconnection1.Connected:=true;
except
showmessage('数据库连接失败，请检查dblink.ini文件中的连接信息的设置是否正确！');
application.Terminate;
end;

end;

procedure Tmainform.N9Click(Sender: TObject);
begin
if MessageDlg('是否确定要离开系统？',
mtConfirmation,[mbYes,mbNo],0)=mrYes then
application.Terminate;
end;

procedure Tmainform.N4Click(Sender: TObject);

var I: integer;
//f_student:Tf_student;
begin
with mainform do
for I:=MDIChildCount-1 downto 0 do
MDIChildren[I].Close;
F_student:=TF_student.Creat(self);
F_student.Show;
end;

end.
错误提示：
[error]unit1.pas(39):Undeclared identifier:'Tf_student'
[Fatal error]unit1.pas(44):Could not compile used unit 'Unit2.pass'

请问这是什么原因啊？

Answer 1

1. Tf_student 类型没有定义。如果你在其它单元定义了，就要引用那个单元。
2. Unite2.pas 存不存在，在工程中有没有加进来？