问一个很菜的问题？

Question

我用DBGrid 的Savetofile 方法保存成txt文件，在用其loadfromfile 方法加载
他，结果只显示列头。TXT文件中也只有列头，而没有数据。
怎么回事啊？：（

Answer 1

unit Unit1;interfaceuses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls, Grids, DBGrids, DB, DBTables, ExtCtrls, DBCtrls;type
  TForm1 = class(TForm)
    DataSource1: TDataSource;
    Table1: TTable;
    DBGrid1: TDBGrid;
    Button1: TButton;
    SaveDialog1: TSaveDialog;
    DBNavigator1: TDBNavigator;
    Table1ID: TAutoIncField;
    Table1XH: TSmallintField;
    Table1XM: TStringField;
    Table1XB: TStringField;
    Table1NL: TSmallintField;
    Table1SZXB: TStringField;
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
    procedure DbgridToTxt(source:Tobject);
  public
    { Public declarations }
  end;var
  Form1: TForm1;implementation{$R *.dfm}procedure TForm1.Button1Click(Sender: TObject);
begin
  DbgridToTxt(dbgrid1);
end;
procedure Tform1.DbgridToTxt(source:Tobject);
var
  filename:Textfile;
  Dataset:Tdataset;
  titlestr,valuestr,tempstr:string;
  counter:integer;
begin
  if (source is Tdbgrid)then
    Dataset:=Tdbgrid(source).DataSource.DataSet
    else
      Dataset:=TDataset(source);
  if ((Dataset.IsEmpty)or(not Dataset.Active))then
    exit else
    begin
      Dataset.DisableControls;
      Dataset.First;
      if savedialog1.Execute then
        begin
          assignfile(filename,savedialog1.FileName);
          rewrite(filename);
          for counter:=0 to Dataset.FieldCount-1 do
          titlestr:=titlestr+char(9)+Dataset.Fields[counter].DisplayLabel;
          titlestr:=trim(titlestr);
          writeln(filename,titlestr);
          while not Dataset.Eof do
            begin
              valuestr:='';
              for counter:=0 to Dataset.FieldCount-1 do
              begin
                tempstr:=Dataset.Fields[counter].Text;
                valuestr:=valuestr+char(9)+tempstr;
              end;
              valuestr:=trim(valuestr);
              writeln(filename,valuestr);
              Dataset.Next;
            end;
              closefile(filename);
          end;
              Dataset.EnableControls;
    end;
end;
              
end.