How to turn on IDENTITY_INSERT with EF in .NET Core

Question

I am building a React web app using .NET Core api and Entity Framework connected to Azure database. The issue is when I try to add a new item through the api's http, I get this error:

SqlException: Cannot insert explicit value for identity column in table 'Products' when IDENTITY_INSERT is set to OFF.

Most of the solutions I found were to add .ValueGeneratedOnAdd() in the context's file to the id column or add this line of code in my Model (above the ID)

        [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
        [Key]
        public int Id { get; set; }

However, none of the solutions worked. Any advices would be appreciated as currently I have no clue how to change that settings without using sql.

Here is also my HttpPost method:

        [HttpPost]
        [Route("CreateProduct")]
        public void AddProduct(Product p)
        {
            ProductHandler _handler = new ProductHandler();
            _handler.CreateProduct(p);
        }

and the handler:

public List<Product> GetProducts()
{
    ApplicationDbContext context;
    using (context = new ApplicationDbContext())
    {
        var listOfProducts = context.Products;
        products.Clear();
        foreach (Product product in listOfProducts)
        {
            products.Add(product);
        }
        context.Dispose();
    }
    return products;
}

public void CreateProduct(Product p)
{
    using (ApplicationDbContext context = new ApplicationDbContext())
    {

        context.Products.Add(p);
        context.SaveChanges();
    }

}

Answer 1

The issue arises when you pass an ID to the backend server, which should not be done. Entity Framework is configured to automatically generate a unique ID for each entity by using the [DatabaseGenerated(DatabaseGeneratedOption.Identity)] attribute. Therefore, you need to ensure that the ID remains at its default value, typically 0, when adding a new entity to the database, allowing EF Core to correctly handle and generate a unique ID for it.

You could create web api app and use test code as follow

[Route("api/[controller]")]
[ApiController]
public class ProductsController : ControllerBase
{
    private readonly ApplicationDbContext _context;

    public ProductsController(ApplicationDbContext context)
    {
        _context = context;
    }

    [HttpPost]
    public async Task<ActionResult<Product>> AddProduct(Product product)
    {
        
        _context.Products.Add(product);
        await _context.SaveChangesAsync();

        return CreatedAtAction("GetProduct", new { id = product.Id }, product);
    }

    
    [HttpGet("{id}")]
    public async Task<ActionResult<Product>> GetProduct(int id)
    {
        var product = await _context.Products.FindAsync(id);

        if (product == null)
        {
            return NotFound();
        }

        return product;
    }
}