private void FillGridViewThongTinNhanVien()
    {
        dgvThongTinNhanVien.Rows.Clear();
        dgvThongTinNhanVien.Columns.Clear();


        DataGridViewTextBoxColumn manv = new DataGridViewTextBoxColumn();
        manv.HeaderText = "Mã NV";
        manv.DataPropertyName = "MaNhanVien";
        dgvThongTinNhanVien.Columns.Add(manv);
        DataGridViewTextBoxColumn chucvu = new DataGridViewTextBoxColumn();
        chucvu.HeaderText = "Chức vụ";
        chucvu.DataPropertyName = "ChucVu";
        dgvThongTinNhanVien.Columns.Add(chucvu);
        DataGridViewTextBoxColumn tennv = new DataGridViewTextBoxColumn();
        tennv.HeaderText = "Tên NV";
        tennv.DataPropertyName = "HoTen";
        dgvThongTinNhanVien.Columns.Add(tennv);
        DataGridViewTextBoxColumn diachi = new DataGridViewTextBoxColumn();
        diachi.HeaderText = "Địa chỉ";
        diachi.DataPropertyName = "DiaChi";
        dgvThongTinNhanVien.Columns.Add(diachi);
        DataGridViewTextBoxColumn email = new DataGridViewTextBoxColumn();
        email.HeaderText = "Email";
        email.DataPropertyName = "Email";
        dgvThongTinNhanVien.Columns.Add(email);
        DataGridViewCheckBoxColumn gioitinh = new DataGridViewCheckBoxColumn();
        gioitinh.HeaderText = "Giới tính";
        gioitinh.DataPropertyName = "GioiTinh";
        dgvThongTinNhanVien.Columns.Add(gioitinh);
        DataGridViewTextBoxColumn ngayvaolam = new DataGridViewTextBoxColumn();
        ngayvaolam.HeaderText = "Ngày vào làm";
        ngayvaolam.DataPropertyName = "NgayVaoLam";
        dgvThongTinNhanVien.Columns.Add(ngayvaolam);
        DataGridViewImageColumn hinh = new DataGridViewImageColumn();
        hinh.HeaderText = "Hình";
        hinh.DataPropertyName = "Hinh";
        hinh.ImageLayout = DataGridViewImageCellLayout.Normal;
        dgvThongTinNhanVien.Columns.Add(hinh);

        QLKSDataContext db = new QLKSDataContext();
        var ttNhanVien = db.spGetAllNhanVien();

        byte[] image;
        MemoryStream ms = new MemoryStream();
        Image img = Properties.Resources.NoImage;
        foreach (var nv in ttNhanVien)
        {
            if (nv.Hinh != null)
                image = (byte[])nv.Hinh.ToArray();
            else {
                    img.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg);

                    image = (byte[])(ms.ToArray());
                 }
            dgvThongTinNhanVien.Rows.Add(nv.MaNhanVien, nv.ChucVu, nv.HoTen, nv.DiaChi, nv.Email, nv.GioiTinh, nv.NgayVaoLam, image);
        }
        for (int i = 0; i < dgvThongTinNhanVien.Columns.Count; i++)
        {
            if (dgvThongTinNhanVien.Columns[i] is DataGridViewImageColumn)
            {
                ((DataGridViewImageColumn)dgvThongTinNhanVien.Columns[i]).ImageLayout = DataGridViewImageCellLayout.Normal;
                break;
            }
        }
        //dgvThongTinNhanVien.DataSource = ttNhanVien;
    }