private void button1_Click(object sender, EventArgs e)
{
SachManager sachManager = new SachManager();
OpenFileDialog theDialog = new OpenFileDialog();
theDialog.Title = "Open Excel File";
theDialog.Filter = "Excel files|*.xlsx";
if (theDialog.ShowDialog() == DialogResult.OK)
{
string path = theDialog.InitialDirectory + theDialog.FileName;
sachManager.saveListSach(excelHelper.GetListSachFromExcel(path));
}
}