Inherits from DbSet with the purposes to add property

Question

Is there a way to inherits from DbSet? I want to add some new properties, like this:

public class PersonSet : DbSet
{
    public int MyProperty         


        

Answer 1

One solution is to create a class that implements IDbSet and delegates all operations to a real DbSet instance, so you can store state.

public class PersonSet : IDbSet
{
    private readonly DbSet _dbSet;

    public PersonSet(DbSet dbSet)
    {
        _dbSet = dbSet;
    }

    public int MyProperty { get; set; }

    #region implementation of IDbSet

    public Person Add(Person entity)
    {
        return _dbSet.Add(entity);
    }

    public Person Remove(Person entity)
    {
        return _dbSet.Remove(entity);
    }

    /* etc */
    #endregion
}

Then in your DbContext, put a getter for your Custom DbSet:

public class MyDbContext: DbContext
{
    public DbSet People { get; set; }

    private PersonSet _personSet;
    public PersonSet PersonSet
    {
        get 
        {
            if (_personSet == null)
                _personSet = new PersonSet( Set() );

            _personSet.MyProperty = 10;

            return _personSet;
        }
        set
        {
            _personSet = value;
        }
    }

}