private void button_danhsach_hocsinh_ItemClick(object sender, DevExpress.XtraBars.ItemClickEventArgs e)
{
thongkedanhsachhocsinh _tk_danhsachhocsinh = new thongkedanhsachhocsinh();
_tk_danhsachhocsinh.MdiParent = this;
_tk_danhsachhocsinh.Show();
}
private void button_danhsach_hocsinh_ItemClick(object sender, DevExpress.XtraBars.ItemClickEventArgs e)
{
thongkedanhsachhocsinh _tk_danhsachhocsinh = new thongkedanhsachhocsinh();
_tk_danhsachhocsinh.MdiParent = this;
_tk_danhsachhocsinh.Show();
}