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I have a segregation of layers as follows:

UI - Web App => References BLL And Entities

BLL - Business Logic (Validations) => References DAL And Entities

Entities - Data Carries (POCO) => No Reference

DAL - Data Context EDMX => No Reference

I have a very basic question, since this is my first project with absolute segregation. If I want to set EntityState (Added/Modified/Deleted) of my objects @ UI level, how do I do that. Because with the above structure I won't have access to the DataContext.

Because for all I know to set the Entity State, data context is a mandate.

I have read a lot questions on SO, but none had a clarification of this doubt. I know one other way would be maintaining a custom State property @ Entities level.

I have read that datacontext should be limited to DAL. Is it a bad practice to set EntityState it @BLL/UI?

I'm new to EF with this kind of architecture.Please help.

I have gone through the following So questions but did not get clarity, may be it is due to my lack of knowledge of SOC:

1.Which layer should create DataContext?

2.Why DbContext object shouldn't be referred in Service Layer?

3.If Entity Framework / DbContext is the DAL / Repository, where does it fit within 3-tier architecture?

4.Entity Framework and layer separation

4.How to update entities which are modified outside the DbContext?

EDIT 1: One thing I'm still concerned about is looping through the object hierarchy again in DAL just to set their EntityState.I have a pretty much nested hierarchy. If I had to do the same in a flat structure I would have to set it once in the UI where objects are filled and can then call context.savechanges().

But here I have made a dummy state property for entity, which I can set @UI and later translate that to EntityState.Modified @DAL. Is this a right approach?

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Pavitar
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  • I'm not understanding why you need to set the entity state in the UI? what do you mean by that? – SOfanatic Oct 02 '14 at 18:09
  • @SOfanatic Lets say i have a grid which represents an entity and i modify the second rows data.I have to mark it as dirty(modified) for my context to know that this entity has to be updated..right? I could be wrong as my experience with EF is very limited – Pavitar Oct 02 '14 at 18:38
  • I guess that would be one way to handle it... but not sure if it's the best way. Just to be clear, your grid is a collection of entities not just 1 single entity right? – SOfanatic Oct 02 '14 at 18:42
  • @SOfanatic - yes a collection entities.I have forms which have data of multiple entities with a nested hierarchy(1 to many) .. so i have to update/add/delete the entire hierarchy based on data user has selected.What are the other ways of handling it, any links refrences would be of great help – Pavitar Oct 02 '14 at 18:47
  • I don't have any links but a better approach would be to do ajax calls? possibly using a client MVVM framework (like knockout.js) – SOfanatic Oct 02 '14 at 20:59

1 Answers1

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Only your DAL should have access to your DataContext (indirectly). The DataContext should be created/retrieved by a ContextFactory that is inserted into your BaseRepository. Somewhere in your factory class you should have a method that retrieves the DataContext: 

public DataContext Get()
{
    return _dataContext ?? (dataContext = new DataContext());
}

Let's say in your repository you have an Update(T entity) method, then that's where you handle the state:

public void Update(T entity)
{
    _dataContext.Entry(entity).State = EntityState.Modified;
}
SOfanatic
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  • This helped me solve another issue of multiple instances of data context. Please check edit 1 of my question. – Pavitar Oct 02 '14 at 07:38