RIA Services Samples Project on CodePlex

It would be nice if you could cover Ria Services Libraries and how to move logic on the server into class libraries while using EF.

Hi Nikhil;

>>What else would you like to see the samples cover?<<
One thing that I'm beginning to see more and more from companies posting jobs for candidates and asking in the requirement section, is that they're looking for candidates with experience in SL3/4, Prism2/4, MEF, MVVM and RIA services. Another words, companies want to start building business apps using RIA with MVVM and Prism/MEF for building decoupled and module apps. I see this becoming a very prominent requirement.

So, my humble suggestion is to provide a real-life LoB app done with RIA and MVVM and MEF to provide a template or architectural blue print how to go about it, so the companies and candidates can both have a better picture what it means to build a SL app using RIA & MVVM & MEF. I had just returned from some meetings that there were many confusing directions and that shows many people don't have a real and clear picture how to go about it and it's like listening to a bunch of blind men describing an elephant. :-)

Thank you in advance!

Nikhil, I have forgotten since I originally looked at this program. In the Web.Config file, when entering the Access and secret Key, do we need to have the "[Access Key]" around the keys or not? e.g.: "[abcde123]" or "abcde123"?
Thanks!

Great idea, just what I was looking for. It is always easier to learn from good examples, like book store app. I hope to see some more unit tests and extensions like fluent metadata!
Also, SilverlightFX is great framework, but because lack of good documentation i couldn't start using it in production, never had time to dig into source.
Thank you for everything and keep up good work!

I would like to see an example that does Inserts and Deletes. Despite promoting Silverlight as a platform that does Line-Of-Business apps, I haven't found any good examples of this out there. (If I recall, even this Bookclub app doesn't do Inserts and Deletes, but only adds and removes from 'My' collection).

It would be nice to see some pattern of what Microsoft recommends as far as this goes.

Thanks,
Rick

Nikhil, it would be nice to see the following scenarios covered in one or more of your samples. I am very surprised to see that people aren't requesting to see these features in action, as these are pretty common scenarios in LOB applications.

1.) Add functionality - it would be nice to see how you handle adding a new item and keeping the Submit button disabled until the new item becomes valid.

2.) Master/Details functionality - it would be nice to see how you handle the above situation, with children in mind as well, so that the Submit button is only valid when the parent and all of its children become valid. Maybe display another grid to display the children of a selected parent?

3.) Derived (Calculated) properties - it would be nice to see how you handle a calculated field on a parent (eg SalesOrder.Total) based on a change in one of its children (eg LineItem.Price). So in this scenario, SalesOrder would raise NotifyPropertyChanged("Total") or similar when one of its childrens .Price values changed.

4.) Extending on 3.), it would be nice to have the option to lazy load AND eager load the children, and being able to reuse the derived property functionality.

Thanks!

To clarify 3.) on my previous post, I envision a domain model pattern, where the parent listens to its children (or DomainContext), and updates itself appropriately when one or many of its childrens' properties changes. So this logic would not be handled in the VM, but rather, within the parent (SalesOrder) itself.

Thanks again!

Nikhil, I'll take a look at your updated code, thanks! Before looking into it, however, would your updated sample (in a master/detail scenario) invalidate the parent and its children when clicking the add button? Thanks again

Nikhil, thanks for your correspondence. I am having difficulty locating the computed properties that you speak of. Which entity contains the logic?

Thanks

Nikhil, those aren't quite what I'm talking about. Let's take the following example, I'll try to be as brief as possible as not to waste your time:

partial class SalesOrder : Entity
{
protected override void OnPropertyChanged(PropertyChangedEventArgs e) {
base.OnPropertyChanged(e);
// ideally, this would execute when a LineItem changed
RaisePropertyChanged("Total");
}

public List<LineItem> LineItems { get; set; }

public decimal Total
{
get { return LineItems.Sum(i => i.Price); }
}
}

public partial class LineItem : Entity
{
public decimal Price { get; set; }
}

So for example, when the following code is executed:

SalesOrder.LineItems[2].Price = 20.25;

SalesOrder would be aware of one of its children changing, thus firing -> RaisePropertyChanged("Total");

And any bound value to SalesOrder.Price would be properly reflected.

Hopefully this makes sense. Currently, I have found this impossible to achieve due to events not being raised as one would think they would be (via DomainContext OR individual change events to child objects). This is disappointing, because to achieve this functionality, I am forced to bury the logic within a VM. This is what I mean by WCF RIA not supporting the Domain Model pattern.

Does this make sense? Am I missing something blatently obvious? For example, are there events I should be subscribing to in order to facilitate this behavior?

One final thing to note is that if you modify a new book, back out the changes, it will remain in a modified state. This has been one of my struggles getting this type of behavior to work.

Thanks again for your continued correspondence.

Nikhil, Thanks.

I get that, I just watered the classes down for sake of brevity.

So basically I'm hearing that there are no available hooks via WCF RIA for reliable notifications, and I'm left on my own to implement my own notification mechanism to get this behavior to work?

I would very much like to see your prototoype. Btw, what is INPC?

In the case of backing out changes, what I meant was typing something into a textBox that is bound to an object property. As soon as you type something in, the object itself == modified, and Entity.PropertyChanged fires. If I back out the changes with the backspace, wiping out everything I typed in, the object is still modified. In addition, the Entity.PropertyChanged event will not fire after this scenario, which makes it impossible to raise events and keep track of child changes based on that fact.

I will love to see some well done sample (at least having compete architecture) on MVVM and MEF by you guys.
MEF and Prism is buzzword. We need strong understanding of the pattern but very few samples are available.