Entity Framework cannot insert data-CodePudding

I am making this a school project and I am first time using the Entity Framework so don't be too harsh about it. These are my tables/classes.

public class Database : DbContext
{
    public Database() {} 

    public DbSet<Producer> Producers { get; set; } 
    public DbSet<Song> Songs { get; set; }
    public DbSet<ProducerSong> ProducerGlasbos { get; set; }
}

public class Song
{
    public int Id { get; set; }
    
    public string Title { get; set; }
    public int Length { get; set; }
    public int Views { get; set; }
}

public class Producer
{
    [DatabaseGenerated(DatabaseGeneratedOption.None)]
    public int Id { get; set; }
    
    public string name { get; set; }
    public string surname { get; set; }
    public int birth { get; set; }
}

public class ProducerSong
{
    [DatabaseGenerated(DatabaseGeneratedOption.None)]
    public int Id { get; set; }
    
    public Producer Producer { get; set; }
    public Song Songs { get; set; }
    
    public int year { get; set; }
}

When I try to inset new instance of a class into table/database in just crashes and throws error

Data.Glasbas.Add(new Glasba { length = 200, Naslov = "Bolecina", views= 313});

Error screenshot: Look at me

Thanks for helping.

CodePudding user response：

You have many to many relations and need to add some navigation properties. Try to change ProducerSong and migrate your db

 public class ProducerSong
    {

       public int  ProducerId { get; set; }
        
        public  int SongId { get; set; }
        
        public  Producer Producer { get; set; }
        
        public  Song Song { get; set; }
        
        public  int year { get; set; }

    }

CodePudding user response：

The problem was in constructors if I used constructors to create objects it just don't work odd but what can you do..

CodePudding user response：

public class Database : DbContext
{
    public Database() { }
    public DbSet<Producer> Producers { get; set; }
    public DbSet<Song> Songs { get; set; }
    public DbSet<ProducerSong> ProducerGlasbos { get; set; }

    public class ProducerSong
    {
        [System.ComponentModel.DataAnnotations.Key]
        public int ProducerSongID { get; set; }

        public Producer Producer { get; set; }
        public Song Songs { get; set; }
        public int year { get; set; }
    }

    public class Song
    {
        [System.ComponentModel.DataAnnotations.Key]
        public int Id { get; set; }

        public string Title { get; set; }
        public int lenght { get; set; }
        public int views { get; set; }

        //ForeignKey
        public int ProducerSongID { get; set; }
        public ProducerSong ProducerSong { get; set; }
    }

    public class Producer
    {
        [System.ComponentModel.DataAnnotations.Key]
        public int Id { get; set; }

        public string name { get; set; }
        public string surname { get; set; }
        public int birth { get; set; }

        //ForeignKey
        public int ProducerSongID { get; set; }
        public ProducerSong ProducerSong { get; set; }
    }
}