如何将响应从c＃类文件发送到MVC控制器

Question

如果我的条件失败为rdr.HasRows == true，我该如何回应我的控制器失败

public Employee DeleteEmpById(int key)
{
    try
    {
        SqlCommand cmd = new SqlCommand("Sp_GetEmployeeById", con);
        cmd.CommandType = CommandType.StoredProcedure;
        cmd.Parameters.AddWithValue("@EmpId", key);
        SqlDataReader rdr = cmd.ExecuteReader();
        if (rdr.HasRows == true)
        {
        }
        else
        // Here what I mention when rdr.HasRows false
    }

控制器

public ActionResult DeleteById(int id)
{
    var x = ObjRepo.DeleteEmpById(id);
    return View(x);
}