NHibernate IsLoaded和Load，例如在Entity Framework中的子集合

Question

I am busy adapting the Microsoft.AspNet.Identity.EntityFramework project to instead use NHibernate for the ORM. It has been fairly easy, with a lot of changes adding async variants for various EF methods where NH has no built-in async.

My biggest concern so far is with code like the following for this (much abridged) DbAspNetUsers class:

public partial class DbAspNetUsers : IDomainEntity<String>  
{
    ...
    public virtual IList<DbAspNetUserClaims> AspNetUserClaimsList{ get; set; }
    ...
}

Now elsewhere, in the original EF UserStore class (hence some name differences), and for more properties than just claims, we have code like the following:

private async Task EnsureClaimsLoaded(TUser user)
{
    if (!Context.Entry(user).Collection(u => u.Claims).IsLoaded)
    {
        var userId = user.Id;
        await _userClaims.Where(uc => uc.UserId.Equals(userId)).LoadAsync().WithCurrentCulture();
        Context.Entry(user).Collection(u => u.Claims).IsLoaded = true;
    }
}

The NH XML mapping for claims is as follows:

<class name="DbAspNetUsers, Core.Data" table="AspNetUsers" lazy='true'>
  ...
  <bag name="AspNetUserClaimsList" inverse="true" cascade="all" lazy='true'>
    <key column="UserId" />
    <one-to-many class="DbAspNetUserClaims, Core.Data" />
  </bag>
  ...
</class>

Does NHibernate have any functionality to cover scenarios like this, or should I simply write methods that do the work of EF's LoadAsync , and then set a Loaded flag, repeated for each child collection?

Any suggestions, commands, or just advice on how to handle this in NH if I can would be greatly appreciated, as would even being convincingly told I cannot do this and must simply load each entity as needed.

Please excuse the terrible naming. I'm using the 'official' mappings generator for the office.

Answer 1

NHibernateUtil.IsInitialized(user.Claims) would give you an idea whether your lazy collection has been loaded.

As for actually loading them, you could either do NHibernateUtil.Initialize() or simply start using the collection (eg calling user.Claims.Count() would cause NH to fetch the collection for you)