请问Delphi导入xls数据时,WorkBook.WorkSheets[1].UsedRange.Rows.Count数据行不准确如何解决？;

Question

xls数据实际上有80条，但在用入下方式导入数据，只能导入30条，请问该问题如何解决？ 
try
        ExcelApp := CreateOleObject('Excel.Application');
        WorkBook := ExcelApp.WorkBooks.Open(dlgOpen1.FileName);//使用opendialog对话框指定
      try           ExcelApp.WorkSheets['A01'].Activate;
            ExcelApp.Visible := false;
           ExcelRowCount := WorkBook.WorkSheets[1].UsedRange.Rows.Count;           for i := 6 to excelrowcount+1  do
           begin
                 A0101 := excelapp.Cells[i,2].Value;  //1
                 A0102:=excelapp.Cells[i,3].Value;  //1
                 A0103:= excelapp.Cells[i,4].Value;    //2
                  with Form1.qry1 do
                  begin
                       close;
                       SQL.clear;
                       sql1:='insert into A01(A0101,A0102,A0103) ';
                       sql1:=sql1+'  values(:A0101,:A0102,:A0103)';
                       sql.add(sql1);
                       Parameters.ParamByName('A0101').Value := A0101;//excel档的第一列插入到aa表的 a 栏位;
                       Parameters.ParamByName('A0102').Value := A0102;//excel档的第二列插入到aa表的 b 栏位;
                       Parameters.ParamByName('A0103').Value := A0103;
                       ExecSQL;
                  end;