如何避免在Entity Framework中加载集合属性

Question

When I select artile, it select user, but user has a collection of article, so article select user again. May be recursive cause out of memory , The calling processing is : article=>user=>article=>user...

ef entities is :

public partial class article
{
public int id { get; set; }
public string title { get; set; }
public string cont { get; set; }
public Nullable<int> uid { get; set; }
public System.DateTime addtime { get; set; }
public Nullable<int> colid { get; set; }

public virtual user user { get; set; }
public virtual column column { get; set; }
}

public partial class user
{
public user()
{
    this.roleusers = new HashSet<roleuser>();
    this.articles = new HashSet<article>();
}

public int id { get; set; }
public string email { get; set; }
public string uname { get; set; }
public string upass { get; set; }

public virtual ICollection<roleuser> roleusers { get; set; }
public virtual ICollection<article> articles { get; set; }
}

mysql EF operation class is :

public class ArtDao
{
    readonly crmEntities _ent = new crmEntities();
    public List<article> PageArts(int start, int limit, out int total)
    {

        var ll =
            _ent.articles.OrderByDescending(o => o.id)
                .Skip(start)
                .Take(limit)
                .ToList();
        total = _ent.articles.Count();
        return ll;
    }

}

How to avoid to eager load the collection property roleusers and articles ?

Answer 1

You need to set LazyLoad on you edmx properties, and manually load only first level childs with Include() method when selecting:

public List<article> PageArts(int start, int limit, out int total)
{

    var ll =
        _ent.articles.OrderByDescending(o => o.id)
            .Skip(start)
            .Take(limit)
            .Include(o => o.user)
            .ToList();
    total = _ent.articles.Count();
    return ll;
}

You need to implement it in another class, wich can be a partial class.