Linq to Sql:在InsertOnSubmit上出错

Question

   private Table<Gallery> galleryTable;
   public GalleryRepository ( string connectionString ) {
        dc = new DataContext(connectionString);
        galleryTable = dc.GetTable<Gallery>();
    }

    public void SaveGallery(Gallery gallery) {

        if (gallery.GalleryId == 0)
            galleryTable.InsertOnSubmit(gallery);
        else if (galleryTable.GetOriginalEntityState(gallery) == null) {
            galleryTable.Attach(gallery);
            galleryTable.Context.Refresh(RefreshMode.KeepCurrentValues, gallery);
        }
        galleryTable.Context.SubmitChanges();
    }

在将新的图库插入到表中时，该方法抛出未设置为对象错误实例的对象引用。图库不为空，galleryTable也不为空

Answer 1

所以问题出在我的Gallery实体上

   private EntitySet<Tag> _Tags;

    [System.Data.Linq.Mapping.Association(Storage = "_Tags", OtherKey = "TagId")]
    public EntitySet<Tag> Tags
    {
        get { return this._Tags; }
        set { this._Tags.Assign(value); }
    }

它在this._Tags.Assign(value);抛出了一个空引用，所以我给_Tags变量分配了一个空的EntitySet，问题就解决了