architecture help: wpf/mvvm data-entry frontend for custom json webservice

I'm finding myself with a bit of anarchitectural problem: I'm working on a smallish project that, among other things, involves data entry and persistance, with a DAL using a webservice with a custom JSON protocol. So far, so good, and it would be a relatively simple matter slapping together some quick&dirty DataTable + DataGrid code and be done with it.

This is a learning project, however, and I'm trying to figure out how to do a somewhat cleaner design, specifically MVVM with a WPF gui, using the Caliburn.Micro framework. The server part is fixed, but I'm doing the entire client part, including the DAL.

With the DG+DT combo, it's pretty easy doing a bunch of edits in the DG, and when user commits simply iterate the Rows, checking the RowState property and firing create/update/delete DAL methods as necessary. DataTable doesn't seem very MVVM databinding-friendly, though, and the ViewModels involved shouldn't care what kind of UI control they're being used with... given that persistance is done through a webservice, requiring batch commit of modifications seems reasonable enough, though.

So I'm pondering what my design options are.

As I understand it, the DAL should deal with model-layer objects (I don't think it's necessary to introduce DTOs for this project), and these will be wrapped in ViewModels before being databound in editor ViewModels.

T开发者_JAVA百科he best idea I've been able to come up with so far is to do a clone of the items-to-be-edited collection when firing up an editor ViewModel, then on commit checking the databound collection against the copy - that'll let me detect new/modified/deleted objects, but seems somewhat tedious.

I've also toyed with the idea of keeping IsModified and IsNewlyCreated properties (I guess those would go in the ViewModel?) - keeping track of deleted items could probably be handled by keeping the editable items in an ObservableCollection, handling the CollectionChanged event, and adding deleted items to a separate list?

As you can see, I'm pretty unsure how to handle this, and any suggestions would be greatly appreciated :)

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First of all

1- Don't do any changes untill you reached a point where you can't live without code changes.

2- As you already said that , you are creating a learning project and you want more modular application so my thoughts would be revolving around how to make my application more modular first before going deep into implementational details.

3- Have you considered using Prism + MVVM framework?

4- I would still suggest that in your ViewModel , you can still use DataTable to bind the data to the grids and byusing DataTable.GetChanges() method will give you all the changes in the table so you don't ever need to maintain boolean varaibles like IsNew or IsModified.

5- If you are not convinced using DataTable yet than use ObservrableCollection to bind data to the grid. ObservrableCollection does not notify indivisual item changed , it will only notify when item are added or removed.