public DataTable KtraTaiKhoan(string TenBang, string TenDangNhap, string MatKhau, ref string err)
{
string id = "";
if (TenBang == "QuanLy")
{
id = "idQuanLy";
}
else if (TenBang == "TacGia")
{
id = "MaTacGia";
}
string sqlkt = "select * from " + TenBang + " where " + id + "=" + "N'" + TenDangNhap + "' and MatKhau=N'" + MatKhau + "'";
return(db.CheckLogin(sqlkt, System.Data.CommandType.Text, ref err));
}