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PODoes it make sense to create new object in Entity Framework before saving it to resolve problems with multiple Contexts?
 

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  1. PODoes it make sense to create new object in Entity Framework before saving it to resolve problems with multiple Contexts?
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    <p>Does it make sense to create new object before trying to save object that I already have loaded but with more then one Context? </p> <p>After lots of tries and errors this code seems to work fine. Basically it's regetting values for <code>Konsultanci</code> and <code>Szkolenie</code> with the current Context based on objects that are read from ObjectListView. </p> <pre><code> var listaDoPodmiany = new List&lt;SzkolenieUczestnicy&gt;(); if (listaUczestnikow.GetItemCount() &gt; 0) { foreach (SzkolenieUczestnicy currentUczestnik in listaUczestnikow.Objects) { using (var context = new EntityBazaCRM(Settings.sqlDataConnectionDetailsCRM)) { if (currentUczestnik.SzkolenieUczestnicyID == 0) { var nowy = new SzkolenieUczestnicy { Konsultanci = context.Konsultancis.First(p =&gt; p.KonsultantNazwa == currentUczestnik.Konsultanci.KonsultantNazwa), Szkolenie = context.Szkolenies.First(p =&gt; p.SzkolenieID == varSzkolenie.SzkolenieID), SzkolenieUzytkownik = currentUczestnik.SzkolenieUzytkownik, SzkolenieUzytkownikData = currentUczestnik.SzkolenieUzytkownikData, UczestnikPotwierdzilUdzial = currentUczestnik.UczestnikPotwierdzilUdzial, UczestnikPrzybyl = currentUczestnik.UczestnikPrzybyl }; context.SzkolenieUczestnicies.AddObject(nowy); context.SaveChanges(); listaDoPodmiany.Add(nowy); } else { context.SzkolenieUczestnicies.Attach(currentUczestnik); context.ObjectStateManager.ChangeObjectState(currentUczestnik, EntityState.Modified); context.SaveChanges(); listaDoPodmiany.Add(currentUczestnik); } } } listaUczestnikow.ClearObjects(); listaUczestnikow.SetObjects(listaDoPodmiany); } </code></pre> <p>This seems to solve lots of problems I was getting about multiple contexts. But is it good approach? Will there be much impact on speed since I guess Konsultanci and Szkolenie will be read another time from SQL?</p> <p>This is continuation (or more like conclusion from multiple questions I asked before):</p> <ul> <li><a href="https://stackoverflow.com/questions/9083709/the-relationship-between-the-two-objects-cannot-be-defined-because-they-are-atta">The relationship between the two objects cannot be defined because they are attached to different ObjectContext objects</a> </li> <li><a href="https://stackoverflow.com/questions/9087427/can-context-of-entity-framework-be-extracted-from-object-later-on">Can context of Entity Framework be extracted from object later on?</a> </li> <li><a href="https://stackoverflow.com/questions/9086722/can-entity-framework-context-be-reused-all-the-time-in-code">Can Entity Framework context be reused all the time in code?</a></li> </ul>
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    1. USCommunity
    1. USMadBoy
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    1. COIf `currentUczestnik` has ID = 0 it was probably not yet added to any context so why to create it again?
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      1. PODoes it make sense to create new object in Entity Framework before saving it to resolve problems with multiple Contexts?
      1. USLadislav Mrnka
    2. COIt's a part of larger code for reupdating... I have updated post to not cause confusion. Also the currentUczestnik has ID=0 but Szkolenie and Konsultanci are already taken from different contexts. Hence the problems..
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      1. USMadBoy
    3. COWhy do you use multiple contexts at the same time?
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      1. USSteven
 

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