函数参数TDataSet类型错误~~~

Question

unit Unit1;interfaceuses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs,DB,ADODB, Grids, DBGrids, StdCtrls;type
  TForm1 = class(TForm)
    ADOConnection1: TADOConnection;
    ADODataSet1: TADODataSet;
    DataSource1: TDataSource;
    DBGrid1: TDBGrid;
    Button1: TButton;
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
    Function ColumnExists(DataSet:TDateSet;sColumn:String):Boolean;  public
    { Public declarations }
  end;var
  Form1: TForm1;implementation{$R *.dfm}
Function TForm1.ColumnExists(DataSet:TDateSet; sColumn:String):Boolean;
var
  T:TField;
begin
  T:=DataSet.FindField(sColumn);
  if Assigned(T) then Result:=true else Result:=false;
end;procedure TForm1.Button1Click(Sender: TObject);
begin
ADODataSet1.close;
ADODataSet1.CommandText:='select * from Dic_City';
ADODataSet1.Open;
if ColumnExists(ADODataSet1,'Code') then
  showmessage('OK');
end;end.
---------------------
ERROR：'Undeclared identifier:'TDataSet''各位请帮忙，先谢过

Answer 1

Function TForm1.ColumnExists(DataSet:（******TDateSet****）; sColumn:String):Boolean;
data

Answer 2

不会吧，我没发现有问题啊。
这个错误是指TDataset没定义，可你明明引用了DB单元的，应该不会有这个错误的。会不会是delphi出问题了？

Answer 3

变量DataSet未申明；
unit Unit1;interfaceuses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs,DB,ADODB, Grids, DBGrids, StdCtrls;type
  TForm1 = class(TForm)
    ADOConnection1: TADOConnection;
    ADODataSet1: TADODataSet;
    DataSource1: TDataSource;
    DBGrid1: TDBGrid;
    Button1: TButton;
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
    Function ColumnExists(DataSet:TDateSet;sColumn:String):Boolean;  public
    { Public declarations }
  end;var
  Form1: TForm1;implementation{$R *.dfm}
Function TForm1.ColumnExists(DataSet:TDateSet; sColumn:String):Boolean;
var
  T:TField;
  DataSet: TDataSet;
begin
  DataSet := TDataSet.Create(Application);
  T:=DataSet.FindField(sColumn);
  if Assigned(T) then Result:=true else Result:=false;
end;procedure TForm1.Button1Click(Sender: TObject);
begin
ADODataSet1.close;
ADODataSet1.CommandText:='select * from Dic_City';
ADODataSet1.Open;
if ColumnExists(ADODataSet1,'Code') then
  showmessage('OK');
end;end.

Answer 4

TDataSet  //對的
TDateSet  //錯的分別就是 a 與 e