c# - need guidelines in creating/updating related entities (is it possible with automapper?) -

i'm new in asp.net mvc , love improve here. used asp.net mvc + ef code first approach. i'm little confuse on how create/update related entites. here's scenario. say,

public class item {   public int id { get; set; }   public string name { get; set; }    public virtual icollection<stock> stocks { get; set; } }  public class stock {   public int id { get; set; }   public int itemid { get; set; }   public int storageid { get; set; }   public float amount { get; set; }    public virtual item item { get; set; }   public virtual storage storage { get; set; } }  public class storage {   public int id { get; set; }   public name { get; set; }    public virtual icollection<stock> stocks { get; set; } } 

so item has 1:many relationship stock. , storage has 1:many relationship stock

in displaying them used automapper worked perfectly. (thanks helping me)

now, i'm trying achieve is.. how create/update entites? (is possible used automapper here?)

say, in 1 post add item, stock, , selected storage. sample code great reference.

any appreciated. thanks

automapper tool map properties of view model to/from domain model.

the view model use in of views, , domain model underlying business model shouldn't exposed views.

this automapper simplifies, maps properties of these 2 models don't have keep on converting 1 model other.

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now moving on creating / updating related entities...

say want add new stock using navigation property on item.

item item = this.dbsource.items.first(itementity => itementity.id == 5);  if(item.stocks == null) item.stocks = new collection<stock>();  item.stocks.add(new stock {     storageid = 3,     amount = 123f });  this.dbsource.savechanges(); 

another case pointed out having new item , x amount of stock of item, want store in database in single operation.

storage storage = this.dbsource.storages.first(storageentity => storageentity.id == 3);  if(storage.stocks == null) storage.stocks = new collection<stock>();  stock stock = new stock {     storageid = 3,     amount = 123f,     item = new item     {         name = "redbull"     } };  storage.stocks.add(stock);  this.dbsource.savechanges(); 

or if have no data in database , want 3 models posted in single go...

stock stock = new stock {     amount = 123f,     item = new item     {         name = "redbull"     } };  storage storage = new storage {     name = "it's secret" };  storage.stocks.add(stock);  this.dbsource.storages.add(storage);  this.dbsource.savechanges(); 

also modify of models constructor initializes collection on of icollection navigational properties, way can avoid nullreferenceexception

so example modify item class this

public class item {     public item()     {         this.stocks = new collection<stock>();     }      public int id { get; set; }     public string name { get; set; }     public virtual icollection<stock> stocks { get; set; } } 

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using item root property

collection<stock> stocks = new collection<stock>(); collection<stock> stocks.add(new stock  {     storageid = 123,     amount = 1000f });   item item = new item {     name = "pizza",     stocks = stocks };   this.dbsource.savechanges();