语句有和错误，该怎么写？

Question

声明没有错误，可能你只声明没定义吧private
    function check_datetime(as_date:string):tdatetime;////////
    { Private declarations }
  public
    ib_flag:boolean;
    { Public declarations }
function check_datetime(as_date:string):tdatetime;////////
beginend;

Answer 1

错误为：[Error] leave.pas(37): Unsatisfied forward or external declaration: 'Tform_vacation.check_datetime'

Answer 2

代码：
unit leave;interfaceuses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
  StdCtrls, Buttons, ComCtrls, Mask, ADODB, Db;type
  Tform_vacation = class(TForm)
    BitBtn_ok: TBitBtn;
    BitBtn_reset: TBitBtn;
    BitBtn_exit: TBitBtn;
    Label_id: TLabel;
    Label_name: TLabel;
    Label_item: TLabel;
    Edit_id: TEdit;
    Edit_name: TEdit;
    Label_begin_date: TLabel;
    Label_end_date: TLabel;
    Label_reason: TLabel;
    Memo_reason: TMemo;
    Label1: TLabel;
    Label2: TLabel;
    MaskEdit_begin: TMaskEdit;
    DateTimePicker_begin: TDateTimePicker;
    DateTimePicker_end: TDateTimePicker;
    MaskEdit_end: TMaskEdit;
    ComboBox_item: TComboBox;
    ADODataSet_temp: TADODataSet;
    ADOQuery1: TADOQuery;
    procedure BitBtn_exitClick(Sender: TObject);
    procedure BitBtn_okClick(Sender: TObject);
    procedure FormShow(Sender: TObject);
    procedure BitBtn_resetClick(Sender: TObject);
  private
    function check_datetime(as_date:string):tdatetime;
    { Private declarations }
  public
    ib_flag:boolean;
    { Public declarations }
  end;var
  form_vacation: Tform_vacation;
  ii_tempid:integer;
implementation
 uses check_data;
{$R *.DFM}
function check_date(as_date:string):tdatetime;
begin
  check_date:=strtodatetime('2002-4-3 12:12:00');
end;procedure Tform_vacation.BitBtn_exitClick(Sender: TObject);
begin
ib_flag:=false;
self.close;
end;procedure Tform_vacation.BitBtn_okClick(Sender: TObject);
var
   ls_datetime_begin:string;
   ls_datetime_end:string;
   ls_type:string;
   ldate_begin:tdatetime;
   ldate_end:tdatetime;
   ls_user_id:string;
   ls_reason:string;
begin
//   if  maskedit_begin.text:='' then
    showmessage(maskedit_begin.text);
    exit;
   ls_datetime_begin:=datetostr(datetimepicker_begin.date) + ' ' + maskedit_begin.Text+':00';
   ls_datetime_end:=datetostr(datetimepicker_end.date) + ' ' + maskedit_end.Text+':00';
//   if ls_datetime_begin then
   try
     begin
      ldate_begin:=strtodatetime(ls_datetime_begin);
      ldate_end:=strtodatetime(ls_datetime_end);
     end;
   except
     begin
      showmessage('δÊäÈëʱ¼äÖµ');
      exit;
     end;
   end;
//showmessage(datetimetostr(datetimepicker_begin.datetime));
//showmessage(datetostr(date()));
   ls_user_id:='1';
   ls_type:=combobox_item.text;
   ls_reason:=memo_reason.lines.text;
   adoquery1.sql.clear;
   adoquery1.SQL.Add('insert into vacation(employee_id,vacation_type,vacation_begin,vacation_end,vacation_causation,user_id)values(:li_id,'''+ls_type+''',:ldate_begin,:ldate_end,'''+ls_reason+''','''+ls_user_id+''')');
   adoquery1.Parameters.ParamByName('ldate_begin').value:=ldate_begin;
   adoquery1.Parameters.ParamByName('ldate_end').value:=ldate_end;
   adoquery1.Parameters.ParamByName('li_id').value:=ii_tempid;
   adoquery1.ExecSQL;
   ib_flag:=true;
   self.close;end;procedure Tform_vacation.FormShow(Sender: TObject);
var
ls_list:tstrings;begin
ib_flag:=false;
ls_list:=tstringlist.Create;
ls_list.add('');
memo_reason.lines:=ls_list;ii_tempid:=form_check.ii_id;if combobox_item.items.Count <= 0 then
begin
combobox_item.items.Add('&Ecirc;&Acirc;&frac14;&Ugrave;');
combobox_item.items.Add('&raquo;é&frac14;&Ugrave;');
combobox_item.items.Add('&sup1;&laquo;&ETH;&Yacute;&frac14;&Ugrave;');
combobox_item.items.Add('&sup2;&iexcl;&frac14;&Ugrave;');
combobox_item.items.Add('&Eacute;&yen;&frac14;&Ugrave;');
combobox_item.items.Add('&sup2;ú&frac14;&Ugrave;');
end;
combobox_item.ItemIndex:=0;   try
    adodataset_temp.close;
    adodataset_temp.CommandText:='select  employee.employee_id,employee.employee_name from employee where employee_id = :li_id';
    adodataset_temp.Parameters.parambyname('li_id').value:=ii_tempid;
    adodataset_temp.open;
    edit_id.text:=adodataset_temp.fields[0].asstring;
    edit_name.text:=adodataset_temp.fields[1].asstring;
   finally
       if adodataset_temp.eof then
          adodataset_temp.last
       else if adodataset_temp.bof then
          adodataset_temp.first;
       adodataset_temp.close;
   end;end;procedure Tform_vacation.BitBtn_resetClick(Sender: TObject);
var
   ls_list:tstrings;
begin
maskedit_begin.text:='';
maskedit_end.text:='';
ls_list:=tstringlist.Create;
ls_list.add('');
memo_reason.lines:=ls_list;
combobox_item.text:='';end;
end.
错误：
[Error] leave.pas(37): Unsatisfied forward or external declaration: 'Tform_vacation.check_datetime'

Answer 3

你声明的是
function check_datetime(as_date:string):tdatetime;
在代码中没有写这个函数体。
而代码中没有写这个函数体是
function check_date(as_date:string):tdatetime 
确没有定义
把这个函数体改成：
function Tform_vacation.check_date(as_date:string):tdatetime 
就行了

Answer 4

错误的意思是：你定义了函数或过程，却没有实现它，
在你的函数实现代码的函数名前加上类的名字 
  function Tform_vacation.check_date(……
因为你定义的是类的成员函数，而你现在却在实现一个单元的私有函数，所以会出错！！我当初也常犯这样的错误，建议你使用右击快捷菜单中的自动完成功能！！