Article: http://www.zzzprojects.com/entity-framework-extensions/docs/how/concurrency

entity-framework-extensions-docs-how-concurrency-example-1.cs

public void BulkSaveChanges_DatabaseWins(DbContext ctx)
{
    bool saveFailed;

    do
    {
        saveFailed = false;

        try
        {
            ctx.BulkSaveChanges();
        }
        catch (DbUpdateConcurrencyException ex)
        {
            saveFailed = true;

            // Update the values of the entity that failed to save from the store 
            ex.Entries.Single().Reload();
        }

    } while (saveFailed); 
}

entity-framework-extensions-docs-how-concurrency-example-2.cs

public void BulkSaveChanges_ClientWins(DbContext ctx)
{
    bool saveFailed;

    do
    {
        saveFailed = false;

        try
        {
            ctx.BulkSaveChanges();
        }
        catch (DbUpdateConcurrencyException ex)
        {
            saveFailed = true;

            // Update original values from the database 
            var entry = ex.Entries.Single();
            entry.OriginalValues.SetValues(entry.GetDatabaseValues()); 
        }

    } while (saveFailed); 
}

entity-framework-extensions-docs-how-concurrency-example-3.cs

public void BulkSaveChanges_CustomResolution(CurrentContext ctx)
        {
public void BulkSaveChanges_CustomResolution(CurrentContext ctx)
{

    bool saveFailed;

    do
    {
        saveFailed = false;

        try
        {
            ctx.BulkSaveChanges();
        }
        catch (DbUpdateConcurrencyException ex)
        {
            saveFailed = true;

            // Get the current entity values and the values in the database 
            // as instances of the entity type 
            var entry = ex.Entries.Single();
            var databaseValues = entry.GetDatabaseValues();

            if (entry.Entity is EntitySimple_Concurrency)
            {
                var clientEntity = (EntitySimple_Concurrency) entry.Entity;
                var databaseEntity = (EntitySimple_Concurrency) databaseValues.ToObject();

                // Choose an initial set of resolved values. In this case we 
                // make the default be the values currently in the database. 
                var resolvedEntity = (EntitySimple_Concurrency) databaseValues.ToObject();

                // Have the user choose what the resolved values should be
                resolvedEntity.IntColumn = clientEntity.IntColumn + 100;
                // ... merge all columns...

                // Update the original values with the database values and 
                // the current values with whatever the user choose. 
                entry.OriginalValues.SetValues(databaseValues);
                entry.CurrentValues.SetValues(resolvedEntity);
            }
        }

    } while (saveFailed);
}

entity-framework-extensions-docs-how-concurrency-example-4.cs

public void BulkUpdate_DatabaseWins<T>(CurrentContext ctx, List<T> list) where T : class
{
    try
    {
        ctx.BulkUpdate(list);
    }
    catch (DbBulkOperationConcurrencyException ex)
    {
        // DO nothing (or log), keep database values!
    }
}

entity-framework-extensions-docs-how-concurrency-example-5.cs

public void BulkUpdate_StoreWins<T>(CurrentContext ctx, List<T> list) where T : class
{
    try
    {
        ctx.BulkUpdate(list);
    }
    catch (DbBulkOperationConcurrencyException ex)
    {
        // FORCE update store entities
        ctx.BulkUpdate(list, operation => operation.AllowConcurrency = false);
    }
}

entity-framework-extensions-docs-how-concurrency-example-6.cs

public void BulkUpdate_CustomResolution<T>(CurrentContext ctx, List<T> list) where T : class
{
    try
    {
        ctx.BulkUpdate(list);
    }
    catch (DbBulkOperationConcurrencyException ex)
    {
        foreach (var entry in ex.Entries)
        {
            ObjectStateEntry objectEntry;

            if (entry is EntitySimple_Concurrency)
            {
                var clientEntry = (EntitySimple_Concurrency) entry;
                var databaseEntry = ctx.EntitySimple_Concurrencys.Single(x => x.ID == clientEntry.ID);

                // merge properties like you want
                clientEntry.IntColumn = databaseEntry.IntColumn;
            }
        }

        // FORCE update store entities
        ctx.BulkUpdate(list, operation => operation.AllowConcurrency = false);
    }
}
 ```