private void btnimport_Click(object sender, EventArgs e)
{
NhapXuatDuLieu nhapDL = new NhapXuatDuLieu();
nhapDL.OnImport += new NhapXuatDuLieu.OnImportHandler(updateAll);
nhapDL.NhapDuLieu();
}
private void btnexport_Click(object sender, EventArgs e)
{
NhapXuatDuLieu xuatDL = new NhapXuatDuLieu();
xuatDL.xuatDuLieu();
}