EF one-to-many to assure the link with the main table.

sblb 1,166

Hi,
I would like to do a link between main table Developer & a table ActionList.

The ActionList take place in edit mode of my app to the address : "/developer/edit/{developerId:int}"

I try to use EF one-to-many to do the link between two tables

I structured the model class has below :

public partial class Developer  
     {  
         public int Id { get; set; }  
          public ICollection<ActionsList>? ActionsLists { get; set; }  
  }  
      
  public class ActionsList  
     {  
         [Key]     
         public int ActionId { get; set; }              
           
         public DateTime ProductionDate { get; set; }  
              
         public int DeveloperId { get; set; }  
         public Developer Developer { get; set; }  
      
     }

application data :

 public class ApplicationDBContext : DbContext  
     {  
         public ApplicationDBContext(DbContextOptions<ApplicationDBContext> options) : base(options)  
         {  
         }  
         public DbSet<Developer> Developers { get; set; }  
         public DbSet<ActionsList> ActionsLists { get; set; }  
                     
          
         protected override void OnModelCreating(ModelBuilder modelBuilder)  
         {  
             modelBuilder.Entity<ActionsList>()  
                         .HasOne<Developer>(s => s.Developer)  
                         .WithMany(g => g.ActionsLists)  
                         .HasForeignKey(s => s.DeveloperId);         
         }     
          
       }

when I want to add the actions in page https://localhost:44354/developer/edit/1 this means all actions for developerId = 1 ; any value has posted in ActionList.

But when I've put the break point await http.PostAsJsonAsync("api/actionslist", act); I see that ActionId = null .

I guess that I set up EF one-to-many wrong!

Can you help me how to link the two tables? (This is the first time I've done this)

Thanks in advance

Zhi Lv - MSFT 32,016 Reputation points Microsoft Vendor

2022-11-14T02:14:18.127+00:00

Hi @sblb ,

The One-to-Many configuration seems correct in above post. More detail information about One-to-Many relationship, see :

One-to-Many Relationship Conventions in Entity Framework Core

Configure One-to-Many Relationships using Fluent API in Entity Framework Core.

But when I've put the break point await http.PostAsJsonAsync("api/actionslist", act); I see that ActionId = null .

Do you mean after calling the API method, the ActionId in the return data is null? From your code, the ActionId is the primary key, by default it is identity and will auto-insert, if it is null, first, you can check the database via the SSMS, whether the ActionsList table contains the relates data. Second, you can check the API method, whether it get the correct data from the database, and the return data is not null. If the issue relates the API method, can you share the relate code?

Accepted answer

AgaveJoe 26,136

Against my better judgement, I created an example. This is an example NOT a solution. In production code you would NOT pass entities between the client and Web API! Typically you would designed a data interrace and pass poco classes.

I used followed the following documentation which I have provided many times over many of your threads.

Tutorial: Create a web API with ASP.NET Core
Saving Related Data

Entities

    public partial class Developer  
    {  
        public int DeveloperId { get; set; }  
        public List<ActionItem>? ActionItems { get; set; }  
    }  
  
    public class ActionItem  
    {  
        public int ActionItemId { get; set; }  
        public string? Tilte { get; set; }  
        public string? Description { get; set; }  
        public string? State { get; set; }  
        public DateTime? OpenDate { get; set; }  
        public DateTime? PlanDate { get; set; }  
        public DateTime? CloseDate { get; set; }  
  
        public int DeveloperId { get; set; }  
        public Developer? Developer { get; set; }

Related data configuration

        protected override void OnModelCreating(ModelBuilder modelBuilder)  
        {  
            modelBuilder.Entity<ActionItem>()  
                .HasOne(d => d.Developer)  
                .WithMany(d => d.ActionItems);  
        }

Controller

    [Route("api/[controller]")]  
    [ApiController]  
    public class DeveloperActionController : ControllerBase  
    {  
        private readonly WebApiSqliteContext _context;  
        public DeveloperActionController(WebApiSqliteContext context)  
        {  
            _context = context;  
        }  
        // GET: api/<DeveloperActionController>  
        [HttpGet]  
        public IEnumerable<Developer> GetDevelopersWithActions()  
        {  
            return _context.Developers.Include(a => a.ActionItems).ToList();  
        }  
  
        // GET api/<DeveloperActionController>/5  
        [HttpGet("{id}")]  
        public async Task<ActionResult<Developer>> GetDeveloperActions(int id)  
        {  
            Developer? developer = await _context.Developers  
                .Include(a => a.ActionItems)  
                .FirstOrDefaultAsync(d => d.DeveloperId == id);  
  
            if (developer == null)  
            {  
                return NotFound();  
            }  
  
            return Ok(developer);  
        }  
  
        // POST api/<DeveloperActionController>  
        [HttpPost]  
        public async Task<ActionResult<Developer>> PostAsync([FromBody] Developer developer)  
        {  
            _context.Developers.Add(developer);  
            await _context.SaveChangesAsync();  
  
            return CreatedAtAction(nameof(GetDeveloperActions), new { id = developer.DeveloperId }, developer);  
        }  
  
        // PUT api/<DeveloperActionController>/5  
        [HttpPut("{id}")]  
        public async Task<ActionResult<Developer>> Put(int id, [FromBody] ActionItem actionItem)  
        {  
            Developer? developer = await _context.Developers  
                .Include(a => a.ActionItems)  
                .FirstOrDefaultAsync(d => d.DeveloperId == id);  
  
            if (developer == null)  
            {  
                return NotFound();  
            }  
  
            developer.ActionItems.Add(actionItem);  
            await _context.SaveChangesAsync();  
  
            return CreatedAtAction(nameof(GetDeveloperActions), new { id = developer.DeveloperId }, developer);  
  
        }  
  
        // DELETE api/<DeveloperActionController>/5  
        [HttpDelete("{id}")]  
        public async Task<IActionResult> Delete(int id)  
        {  
            Developer? developer = await _context.Developers  
                .Include(a => a.ActionItems)  
                .FirstOrDefaultAsync(d => d.DeveloperId == id);  
  
            if (developer == null)  
            {  
                return NotFound();  
            }  
  
            _context.Remove(developer);  
  
            await _context.SaveChangesAsync();  
  
            return NoContent();  
        }  
    }

Post data

{  
  "developerId": 0,  
  "actionItems": [  
    {  
      "actionItemId": 0,  
      "tilte": "Action Title",  
      "description": "Description",  
      "state": "State",  
      "openDate": "2022-11-17",  
      "planDate": "2022-11-17",  
      "closeDate": "2022-11-17",  
      "developerId": 0  
    }  
  ]  
}

Put data

{  
  "actionItemId": 0,  
  "tilte": "Action Title 2",  
  "description": "Description 2",  
  "state": "State 2",  
  "openDate": "2022-11-18",  
  "planDate": "2022-11-18",  
  "closeDate": "2022-11-18",  
  "developerId": 1  
}

Configuration is needed to return a entity otherwise you'll get an error.

builder.Services.AddControllers().AddJsonOptions(x =>  
                x.JsonSerializerOptions.ReferenceHandler = ReferenceHandler.IgnoreCycles);

13 additional answers

AgaveJoe 26,136 Reputation points

2022-11-22T13:50:50.193+00:00

The Developer class you've shared is a partial class. I'm wondering if there is another partial class that defines a primary key named Id which makes this whole thread is a waste of everyone's time.
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sblb 1,166 Reputation points

2022-11-22T14:12:09.097+00:00

does this mean that my problem is that I am using a partial class? Right?
I confirm that there is no other partiel class.

I handed over the FK with DeveloperId and I' always the charge utile with developoerId : null

AgaveJoe 26,136 Reputation points

2022-11-22T15:05:53.14+00:00

does this mean that my problem is that I am using a partial class? Right?

Your response tells me you have no idea what a partial class is.

I confirm that there is no other class

I suspect this response is not true. In previous threads you had a Developer class with properties like ECO and ECR. If I recall, in this thread you removed the [Required] attributes from a few properties in order to post a Developer class. I suspect there is another Developer partial class with, perhaps, an "Id" property. This explains why the ActionItem class has an "Id" property that is not the ActionItem's primary key. Of course, there could be another explanation as we cannot see all the relevant code.

I think what's happened is similar to all your threads. You are copying and pasting code blocks hoping a random combination of code will magically solve a goal. That causes you to ask questions that have nothing to do with the actual problem. For example, in this thread you ask how to save related records because you assumed that's the problem. The reality is you have no idea how your code works.

I recommend committing the code to GitHub because we cannot trust your assumptions. We need the actual code not your presumption.

Please start a new thread.

sblb 1,166 Reputation points

2022-11-22T16:28:55.36+00:00

Ok I will prepare an extract of my application and push on Github. How I can share the github link in private?

AgaveJoe 26,136 Reputation points

2022-11-22T16:48:59.437+00:00

How I can share the github link in private?

Perhaps try reading the GitHub docs...

About repositories

sblb 1,166 Reputation points

2022-11-22T21:25:35.84+00:00

You can find here github link AppWebFK
Do you want continuous in this thread?
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sblb 1,166

The foreign key (DeveloperId) is required to relate the ActionItem to the Developer.

I understand that. In the example above I wanted to show you that I could populate the ActionITem w/o link with Developer.

Most importantly, there is no indication the Blazor application actually populates the DeveloperId property which you named "Id".

I renamed it like you ie Id becomes DeveloperId

 public partial class Developer  
    {  
        public int DeveloperId { get; set; }  
        public List<ActionItem>? ActionItems { get; set; }  
  
}  
  
 public class ActionItem  
    {  
        [Key]  
        public int ActionId { get; set; }         
        public string? Tilte { get; set; }  
        public string? DescriptionA { get; set; }          
        public string? State { get; set; }          
        public DateTime? OpenDate { get; set; }         
        public DateTime? PlanDate { get; set; }         
        public DateTime? CloseDate { get; set; }  
          
      public int DeveloperId { get; set; }  
       public Developer? Developer { get; set; }  
    }

When I want to use the foreign key so DeveloperId I always have the same problem.

Can you see where I have the problem?

sblb 1,166

You will find below two controllers and code behind for the ActionItem :

DeveloperController :

 [HttpGet]  
        public async Task<IActionResult> Get()  
        {  
            var devs = await _context.Developers.ToListAsync();  
            return Ok(devs);  
        }  
  
        [HttpGet("{id}")]  
        public async Task<IActionResult> Get(int id)  
        {  
            var dev = await _context.Developers.FirstOrDefaultAsync(a => a.DeveloperId == id);  
            return Ok(dev);  
        }         
  
        //Take a number ECO  
        [HttpGet("GenearteEcoById/{id}")]  
        public async Task<ActionResult<Developer>> GenearteEcoById(int id)  
        {  
            var developer = await _context.Developers.FindAsync(id);  
            if (developer == null)  
            {  
                return NotFound();  
            }  
            if (developer.ECOYear == 0 && developer.ECOCount == 0 && developer.ECOSelected==true)  
            {  
                var values = await GenerateEcoByIdAsync(id);  
                developer.ECOYear = values.Year;  
                developer.ECOCount = values.Count;  
                await _context.SaveChangesAsync();  
            }  
            else if(developer.ECOSelected == false)  
            {  
                developer.ECOYear = 0;  
                developer.ECOCount = 0;  
                await _context.SaveChangesAsync();  
  
            }  
  
            return developer;  
        }  
          
        private async Task<YearCount> GenerateEcoByIdAsync(int id)  
        {  
            if (!await _context.Developers.AnyAsync(d => d.ECOYear == DateTime.Now.Year))  
            {  
                return new YearCount() { Count = 1, Year = DateTime.Now.Year };  
            }  
  
            int max = await _context.Developers.Where(d => d.ECOYear == DateTime.Now.Year).MaxAsync(d => d.ECOCount) + 1;  
            return new YearCount() { Count = max, Year = DateTime.Now.Year };  
        }  
  
        //Creates a new Developer with the passed developer object data AND take ECR Number  
        [HttpPost]  
        public async Task<IActionResult> Post(Developer developer)  
        {  
                     
            YearCount dev = await IncrementDeveloperIdAsync();  
  
            developer.Year = dev.Year;  
            developer.Count = dev.Count;  
  
            _context.Add(developer);  
            await _context.SaveChangesAsync();  
            return Ok(developer.DeveloperId);  
             
        }       
  
  
        //Take the number ECR  
        private async Task<YearCount> IncrementDeveloperIdAsync()  
        {  
            if (!await _context.Developers.AnyAsync(d => d.Year == DateTime.Now.Year))  
            {  
                return new YearCount() { Count = 1, Year = DateTime.Now.Year };  
            }  
  
            int max = await _context.Developers.Where(d => d.Year == DateTime.Now.Year).MaxAsync(d => d.Count) + 1;  
            return new YearCount() { Count = max, Year = DateTime.Now.Year };  
        }  
  
        //Modifies an existing developer record.  
        [HttpPut]  
        public async Task<IActionResult> Put(Developer developer)  
        {  
            _context.Entry(developer).State = EntityState.Modified;  
            await _context.SaveChangesAsync();  
            return NoContent();  
        }  
  
        [HttpDelete("{id}")]  
        public async Task<IActionResult> Delete(int id)  
        {  
            var dev = new Developer { DeveloperId = id };  
            _context.Remove(dev);  
            await _context.SaveChangesAsync();  
            return NoContent();  
        }

the data is fetch in datagrid view below

So after that I edit the page

DeveloperActionController.cs

// GET: api/<DeveloperActionController>  
        [HttpGet]  
        public IEnumerable<Developer> GetDevelopersWithActions()  
        {  
            return _contexts.Developers.Include(a => a.ActionItems).ToList();  
        }  
  
        // GET api/<DeveloperActionController>/5  
        [HttpGet("{id}")]  
        public async Task<ActionResult<Developer>> GetDeveloperActions(int id)  
        {  
            Developer? developer = await _contexts.Developers  
                                                  .Include(a => a.ActionItems)  
                                                  .FirstOrDefaultAsync(d => d.DeveloperId == id);  
  
            if (developer == null)  
            {  
                return NotFound();  
            }  
  
            return Ok(developer);  
        }  
  
        // POST api/<DeveloperActionController>/AddAction  
        [HttpPost("/api/DeveloperAction/AddActionItem")]  
        public async Task<ActionResult<Developer>> PostActionItem([FromBody] ActionItem actionItem)  
        {  
            _contexts.ActionItems.Add(actionItem);  
            await _contexts.SaveChangesAsync();  
  
            return CreatedAtAction(nameof(GetDeveloperActions), new { id = actionItem.DeveloperId }, actionItem);  
        }  
  
  
        // PUT api/<DeveloperActionController>/5  
        [HttpPut("{id}")]  
        public async Task<ActionResult<Developer>> Put(int id, [FromBody] ActionItem actionItem)  
        {  
            Developer? developer = await _contexts.Developers  
                                                  .Include(a => a.ActionItems)  
                                                  .FirstOrDefaultAsync(d => d.DeveloperId == id);  
  
            if (developer == null)  
            {  
                return NotFound();  
            }  
  
            developer.ActionItems.Add(actionItem);  
            await _contexts.SaveChangesAsync();  
  
            return CreatedAtAction(nameof(GetDeveloperActions), new { id = developer.DeveloperId }, developer);  
  
        }  
  
        // DELETE api/<DeveloperActionController>/5  
        [HttpDelete("{id}")]  
        public async Task<IActionResult> Delete(int id)  
        {  
            Developer? developer = await _contexts.Developers  
                .Include(a => a.ActionItems)  
                .FirstOrDefaultAsync(d => d.DeveloperId == id);  
  
            if (developer == null)  
            {  
                return NotFound();  
            }  
  
            _contexts.Remove(developer);  
  
            await _contexts.SaveChangesAsync();  
  
            return NoContent();  
        }

in code behind I initialize and I use post method to populate ActionItem

   protected override async Task OnInitializedAsync()  
    {  
        actionitems = await http.GetFromJsonAsync<ActionItem[]>("api/developeractions");  
  
    }        
  
    async Task CreateActionList()  
    {          
      // await http.PostAsJsonAsync($"api/developer/edit/{developerId}/developeractions", act);  
       await http.PostAsJsonAsync($"api/developeractions/AddActionItem", act);        
       uriHelper.NavigateTo($"/developer/edit/{developerId}");  
    }

In Edit page I should see the ActionItem data in datagridview but The new row is created with DeveloperController instead of DeveloperActionsController. It's real mystery!!

AgaveJoe 26,136 Reputation points

2022-11-21T20:57:56.947+00:00

In Edit page I should see the ActionItem data in datagridview but The new row is created with DeveloperController instead of DeveloperActionsController. It's real mystery!!

Your code specifically redirects to /developer/edit/{developerId}. I assume component calls the developer controller. Why do you think otherwise?

I assume the AddActionItem is not working as you expected because you still have not added the correct developerId to the post payload.
This bug in your code has been identified yet you continue to do the same thing excepting a different result.

sblb 1,166

Your code specifically redirects to /developer/edit/{developerId}.

Yes I use uriHelper.NavigateTo($"/developer/edit/{developerId}"); to ensure that when I validated the user stay in page edit.

I assume component calls the developer controller. Why do you think otherwise?

the component calls developeractions await http.PostAsJsonAsync($"api/developeractions/AddActionItem", act);

My concern is when I add the FK, why do I not populate ActionItem?

I tried the following control w/o FK again and in this case everything works fine to populate ActionItem:

 [HttpGet]  
        public async Task<IActionResult> Get()  
        {  
            var actions = await _contexts.ActionItems.ToListAsync();  
            return Ok(actions);  
        }  

        [HttpGet("{id}")]  
        public async Task<IActionResult> Get(int id)  
        {  
            var action = await _contexts.ActionItems.FirstOrDefaultAsync(a => a.ActionId == id);  
            return Ok(action);  
        }  

        [HttpPost]  
        public async Task<IActionResult> Post(ActionItem actions)  
        {  
            _contexts.Add(actions);  
            await _contexts.SaveChangesAsync();  
            return Ok(actions.ActionId);  
        }

AgaveJoe 26,136 Reputation points

2022-11-22T12:34:33.01+00:00

My concern is when I add the FK, why do I not populate ActionItem? I tried the following control w/o FK again and in this case everything works fine to populate ActionItem:

Not true...

The foreign key (DeveloperId) is required to relate the ActionItem to the Developer. If there's no foreign key then the relationship is broken or the ActionItem is assigned to DeveloperId zero.

Most importantly, there is no indication the Blazor application actually populates the DeveloperId property which you named "Id".

The Blazor application has many problems. Troubleshoot and fix your code.

sblb 1,166

I've made the same controller like you.
Should I delete the controller named DeveloperController.cs?

I've always actionsitem = null

  [Route("api/[controller]")]  
    [ApiController]  
    public class DeveloperActionsController : ControllerBase  
    {  
        private readonly ApplicationDBContext _contexts;  
  
        public DeveloperActionsController(ApplicationDBContext contexts)  
        {  
            this._contexts= contexts;  
        }  
  
        // GET: api/<DeveloperActionController>  
        [HttpGet]  
        public IEnumerable<Developer> GetDevelopersWithActions()  
        {  
            return _contexts.Developers.Include(a => a.ActionItems).ToList();  
        }  
  
        // GET api/<DeveloperActionController>/5  
        [HttpGet("{id}")]  
        public async Task<ActionResult<Developer>> GetDeveloperActions(int id)  
        {  
            Developer? developer = await _contexts.Developers  
                .Include(a => a.ActionItems)  
                .FirstOrDefaultAsync(d => d.DeveloperId == id);  
  
            if (developer == null)  
            {  
                return NotFound();  
            }  
  
            return Ok(developer);  
        }  
  
     // POST api/<DeveloperActionController>/AddAction  
    [HttpPost("/api/DeveloperAction/AddActionItem")]  
    public async Task<ActionResult<Developer>> PostActionItem([FromBody] ActionItem actionItem)  
    {  
        _contexts.ActionItems.Add(actionItem);  
        await _contexts.SaveChangesAsync();  

        return CreatedAtAction(nameof(GetDeveloperActions), new { id = actionItem.DeveloperId }, actionItem);  
    }  
  
        // PUT api/<DeveloperActionController>/5  
        [HttpPut("{id}")]  
        public async Task<ActionResult<Developer>> Put(int id, [FromBody] ActionItem actionItem)  
        {  
            Developer? developer = await _contexts.Developers  
                .Include(a => a.ActionItems)  
                .FirstOrDefaultAsync(d => d.DeveloperId == id);  
  
            if (developer == null)  
            {  
                return NotFound();  
            }  
  
            developer.ActionItems.Add(actionItem);  
            await _contexts.SaveChangesAsync();  
  
            return CreatedAtAction(nameof(GetDeveloperActions), new { id = developer.DeveloperId }, developer);  
  
        }  
  
        // DELETE api/<DeveloperActionController>/5  
        [HttpDelete("{id}")]  
        public async Task<IActionResult> Delete(int id)  
        {  
            Developer? developer = await _contexts.Developers  
                .Include(a => a.ActionItems)  
                .FirstOrDefaultAsync(d => d.DeveloperId == id);  
  
            if (developer == null)  
            {  
                return NotFound();  
            }  
  
            _contexts.Remove(developer);  
  
            await _contexts.SaveChangesAsync();  
  
            return NoContent();  
        }

AgaveJoe 26,136 Reputation points

2022-11-21T18:26:01.84+00:00

The ActionItems property is null because your code does not populate the property. I've provided sample code, JSON, and links that illustrate this fundamental concept. Honestly, I'm not sure why you are unable to populate a C# object.
sblb 1,166 Reputation points

2022-11-21T18:54:50.487+00:00
I know you given me a lot information. But I don't understand why it doesn't work.

If I put Post method below I populate ActionItem

[HttpPost] public async Task<IActionResult> Post(ActionsList actions) { _contexts.Add(actions); await _contexts.SaveChangesAsync(); return Ok(actions.ActionId); }

When I introduce the foreign key ActionItem is not populate, why?
AgaveJoe 26,136 Reputation points

2022-11-21T19:18:31.77+00:00
I've provided the Web API data interface two different ways for inserting new records.

1) Passing a new Developer object with ActionItems populated according to your model in this post.

{ "developerId": 0, "actionItems": [ { "actionItemId": 0, "tilte": "Action Title", "description": "Description", "state": "State", "openDate": "2022-11-17", "planDate": "2022-11-17", "closeDate": "2022-11-17", "developerId": 0 } ] }

2) Passing a new ActionItem for an existing developer

{ "actionItemId": 0, "tilte": "Action Title 2", "description": "Description 2", "state": "State 2", "openDate": "2022-11-18", "planDate": "2022-11-18", "closeDate": "2022-11-18", "developerId": 1 }

I also provided PUT actions to update data. For example, adding an ActionItem to a developer.

Lastly, I recommend getting Swagger working which documents the actual payload.

Up to this point there is no indication that you've done anything to move forward.
sblb 1,166 Reputation points

2022-11-21T20:00:28.033+00:00

I guess that you have understood.

I have two tables with main table Developer with the DeveloperController and another table ActionItem with DeveloperActionsController associate with one row of the Developer

So I thought I should use to one-to-many in my case but it's seems that it's not correct!!

Thanks to your help!!! I don't how I can do that.
AgaveJoe 26,136 Reputation points

2022-11-21T20:24:45.513+00:00

So I thought I should use to one-to-many in my case but it's seems that it's not correct!!

Both examples are one-to-many!