与 Web API 的一对多关系不起作用

Question

I have a UserData class which holds all user information eg name, age, height, weight etc. I also have a WorkoutData class which holds all information of a gym workout eg date, workout duration, workout details, calories burned etc.

A user can have many personal workouts associated with it, therefore it also has a List of WorkoutData which represents all of a users past workouts.

When a user adds(posts) a workout I will need the workout to be added to the List in the UserData object, so when I get a User it will show all of the users workouts from the list. Although I am not quite sure how to do this, or the correct way to do it.

UserData and WorkoutData:

namespace FitnessTracker
{
    //holds all user information
    public class UserData
    {
        //Upper bounds for BMI categories
        const double SeverelyUnderweightUpper = 15.9;
        const double UnderweightUpper = 18.4; 
        const double NormalWeightUpper = 24.9;
        const double OverweightUpper = 29.9;
        const double ModeratelyObeseUpper = 34.9;

        public int ID { get; set; }
        [Required(ErrorMessage = "First Name is required")]
        [Display(Name = "First Name")]
        [StringLength(20, ErrorMessage = "First name cannot exceed 20 characters. ")]
        public string FirstName { get; set; }
        [Required(ErrorMessage = "Second Name is required")]
        [Display(Name = "Second Name")]
        [StringLength(20, ErrorMessage = "Second name cannot exceed 20 characters. ")]
        public string SecondName { get; set; }
        public string Gender { get; set; }
        [Range(5, 110, ErrorMessage = "Please enter a valid age. ")]
        public int Age { get; set; }
        [Display(Name = "Weight (KG)")]
        [Range(5, 150, ErrorMessage = "KG must be between 5 and 150")]
        public double WeightKG { get; set; }
        [Display(Name = "Height (CM)")]
        [Range(5, 220, ErrorMessage = "Height must be between 5 and 220 CM")]
        public int HeightCM { get; set; }

        //returns a value for user BMR
        public double BMR
        {
            get
            {
                double bmr = (10 * WeightKG) + (6.25 * HeightCM) - (5 * Age) - 161;
                return bmr;
            }
        }

        //show current saved stats, allow to change to up-do-date stats - check BMR/BMI 
        //return a value for user BMI
        public double BMIValue
        {
            get
            {
                double bmi = (WeightKG / HeightCM / HeightCM) * 10000;
                return bmi;
            }
        }


        public string BMICategory
        {

            get
            {
                double userBMI = this.BMIValue;
                if(userBMI <= SeverelyUnderweightUpper)
                {
                    return "Severely Underweight";
                }
                else if(userBMI <= UnderweightUpper)
                {
                    return "Underweight";
                }
                else if(userBMI <= NormalWeightUpper)
                {
                    return "Normal";
                }
                else if(userBMI <= OverweightUpper)
                {
                    return "Overweight";
                }
                else if(userBMI <= ModeratelyObeseUpper)
                {
                    return "Moderately Obese";
                }
                else
                {
                    throw new Exception("BMI Category Error");
                }
            }
        }




        //Users list of personal workouts
        public List<WorkoutData> Workouts { get; set; }

    }
    //holds all workout information such as start/end times, workout details, calories burned etc.
    public class WorkoutData
    {
        public int ID { get; set; }
        [Required(ErrorMessage = "Date of workout is required")]
        public DateTime Date { get; set; }
        [Display(Name = "Workout Length")]
        public double WorkoutDuration { get; set; }
        [Display(Name = "Workout Details")]
        public string WorkoutDetails { get; set; }
        [Display(Name = "Calories Burned")]
        public int CaloriesBurned { get; set; }       
        public UserData User { get; set; }
    }

}

My UserDataController get method (I need this to display all user information and all of a users workouts from the List):

 [HttpGet]
        public async Task<ActionResult<IEnumerable<UserData>>> GetUsers()
        {
            return await _context.Users.Include(r => r.Workouts).ToListAsync();
        }

My WorkoutDataController post method:

[HttpPost]
    public async Task<ActionResult<WorkoutData>> PostWorkoutData(WorkoutData workoutData)
    {
        _context.Workouts.Add(workoutData);
        await _context.SaveChangesAsync();



        return CreatedAtAction("GetWorkoutData", new { id = workoutData.ID }, workoutData);
    }

Can anyone tell me how to add the workout to the Users List in the above post method? Or if I should do it a different way please advise

Answer 1

You should add a foreign key property for the user to your WorkoutData class.

public int UserID { get; set; }

Then when you POST the WorkoutData in your API action, explicitly set that UserID and EF will take care of the linking. With that navigation link established, your Include clause in the GetUsers() method should properly include the relevant WorkoutData for each user.