private void butExcel_Click(object sender, System.EventArgs e)
{
d.check_process_Excel();
string tenfile = (b_baohiem)?d.Export_Excel(dt, ReportFile.Substring(0, ReportFile.Length - 4)):d.Export_Excel(ds, ReportFile.Substring(0, ReportFile.Length - 4));
oxl = new Excel.Application();
owb = (Excel._Workbook)(oxl.Workbooks.Open(tenfile, Missing.Value, Missing.Value, Missing.Value, Missing.Value, Missing.Value, Missing.Value, Missing.Value, Missing.Value, Missing.Value, Missing.Value, Missing.Value, Missing.Value));
osheet = (Excel._Worksheet)owb.ActiveSheet;
oxl.ActiveWindow.DisplayGridlines = true;
oxl.ActiveWindow.DisplayZeros = false;
osheet.PageSetup.Orientation = XlPageOrientation.xlLandscape;
osheet.PageSetup.PaperSize = XlPaperSize.xlPaperA4;
osheet.PageSetup.LeftMargin = 20;
osheet.PageSetup.RightMargin = 20;
osheet.PageSetup.TopMargin = 30;
osheet.PageSetup.CenterFooter = "Trang : &P/&N";
oxl.Visible = true;
}