Saving changes to child collections with Entity Framework

Question

I have made changes to an EntityCollection which is an object of another EntityCollection, and when I try to save those changes, I get the following error:

The EntityCollection has already been initialized. The InitializeRelatedCollection method should only be called to initialize a new EntityCollection during deserialization of an object graph.

Any ideas what I might be missing?

The following is the code I used.

public void UpdateCompanyManagement(Company newCompany)
{
    Company oldCompany = entities.Companies.Where(c => c.COM_ID == newCompany.COM_ID).SingleOrDefault();

    oldCompany.Managements = newCompany.Managements;

    try
    {
        entities.SaveChanges();
    }
    catch (OptimisticConcurrencyException)
    {
        entities.Refresh(RefreshMode.ClientWins, newCompany.Managements);
        entities.SaveChanges();
    }
}

I'm able to save the parent collection successfully, using the following code:

public void UpdateCompanyDetails(Company newCompany)
{
    Company oldCompany = entities.Companies.Where(c => c.COM_ID == newCompany.COM_ID).SingleOrDefault();
    entities.ObjectStateManager.ChangeObjectState(oldCompany.city, System.Data.EntityState.Modified);
    oldCompany = newCompany;

    try
    {
        entities.SaveChanges();
    }
    catch (OptimisticConcurrencyException)
    {
        entities.Refresh(RefreshMode.ClientWins, oldCompany);
        entities.SaveChanges();
    }
}

score 2 · Answer 1 · edited May 23 '17 at 12:25

2

As far as I understand, you are effectively trying to change parent of elements in Management collection. EF has hard time trying to understand your intention.

Similar problems were answered here available here.

edited May 23 '17 at 12:25

Community

1
1

answered Feb 26 '12 at 20:52

Dmitry Sevastianov

391
2
14

Does it answer your question? – Dmitry Sevastianov Mar 05 '12 at 15:22
Actually @dmitry the resources were very informative, but aren't the same in this case. I've posted a solution that worked for me. – Ibrahim Dauda Dec 19 '15 at 06:07

score 0 · Accepted Answer · answered Dec 19 '15 at 06:04

After much research, I found a problem in my database/model setup (since I'm using a legacy database). Most of the tables in my database had no Primary Key, and those that did, had no Identity Specification and this was causing problems. So I corrected the database and updated my model.

And, I eventually found a simple way to write clean EF code.

The code in both functions could be re-written as follows:

public void UpdateCompanyManagement(Company company, int mgmtID)
{
    var management = company.Managements.Where(m => m.M_ID == mgmtID).SingleOrDefault();

        management.name = "new name";
        management.position = "new position";

        // edit all you want, then save
        // no further code is required
        // except you've done something wrong somewhere

    try
    {
        entities.SaveChanges();
    }
    catch (OptimisticConcurrencyException)
    {
        entities.Refresh(RefreshMode.ClientWins, company);
        entities.SaveChanges();
    }
}

and also,

public void UpdateCompanyDetails(Company company)
{
    company.name = "new company name";
    company.address = "new company address";

    // edit all you want then save
    // no further code is required
    // except you've done something wrong somewhere

    try
    {
        entities.SaveChanges();
    }
    catch (OptimisticConcurrencyException)
    {
        entities.Refresh(RefreshMode.ClientWins, company);
        entities.SaveChanges();
    }
}

Thanks, Peter the Viking! :)

Saving changes to child collections with Entity Framework

2 Answers2