SilverlightShow: Building N-Tier business applications with WCF RIA Services – Part II Comments

Re: Building N-Tier business applications with WCF RIA Services – Part II

WaleedSeada — Sat, 30 Jul 2011 22:22:31 GMT

Hello Zoltan,

Just a simple question regards the entitycollection: public EntityCollection Products;

can we have a client side validation on that collection to check for duplicates in entity entries or something like that using the shared.cs files after decorating the property with the [CustomValidation(typeof(CustomDailyValidation), "ValidateDuplicateIds")] attribute?

so the final result qould be :

[CustomValidation(typeof(CustomValidation), "ValidateDuplicateIds")]

public EntityCollection Products;

If you can give a small example would be great.

Regards

Waleed

RE: Building N-Tier business applications with WCF RIA Services – Part II

zoltan.arvai — Wed, 14 Jul 2010 14:37:27 GMT

Rüdiger: No charts here or RIA Services, just plain old WCF, and POCO with SL + MVVM (didn't even touch a real persistance layer) I think it show the concepts you need in your above example.

http://www.silverlightshow.net/items/Data-Driven-Applications-with-MVVM-Part-I.-The-Basics.aspx

RE: Building N-Tier business applications with WCF RIA Services – Part II

Rüdiger — Wed, 14 Jul 2010 12:00:07 GMT

1. I have lots of business functions residing on the server in Plain Old CLR Objects (simple objects and collections). What I am looking for is an example using WCF/RIA for the client-server part. Does anyone have a URL?

2. We always see the database loading examples, and I am thankful to those providing these;

However, what I think would be interesting is to see e.g. a SL treeview in MVVM in concert with a SL interactive chart in MVVM which could be bound to an observable collection that automatically updates server data via WCF using a custom (POCO) object structure, and only in the end accessing the data layer with either DataSet or EF or SQL connection.

RE: Building N-Tier business applications with WCF RIA Services – Part II

zoltan.arvai — Wed, 16 Jun 2010 15:22:23 GMT

Mr Promo. You dont have to go with the generated code if you don't want to... You can write it from ground up.

RE: Building N-Tier business applications with WCF RIA Services – Part II

zoltan.arvai — Wed, 16 Jun 2010 15:21:32 GMT

Hi Andy!

I'm not really executing business logic on the client side... What I actually do is download data from the server and passing it to he silverlight client to present it on the UI. I think using linq queries are pretty natural by now. While in simple WCF you have to write all the operations (get operations) to just get what you want, in WCF RIA Services, you don't have to do that. You can tell on the client what exactly do you need. (Of course it has constraints). The query by the way runs on the server, you just get the results. I'm pretty sure that's not conflicting with n-tier concepts. (We have presentation tier and a WCF (service layer) as well, and an EF provides DAL like ORM layer:) Definitely not so clear as your solution however your approach takes a lot of extra work to develop. This is out of the box.

RE: Building N-Tier business applications with WCF RIA Services – Part II

Mr. Pomo — Thu, 03 Jun 2010 01:33:47 GMT

After looking at all the stringent requirements and after seeing all the codgen create by these projects, all i have to say is, this technology will never last. Thanks

RE: Building N-Tier business applications with WCF RIA Services – Part II

Andy — Wed, 19 May 2010 20:57:37 GMT

Hi, I'm probably missing something here as I'm trying to understand the difference between a "conventional" WCF service as would be used in an ASP.Net app (pre-VS2010), and an RIA service, where domain services fit in, etc.

In your article under the heading "Simple Query Model" you demonstrate a client-side LINQ query to retrieve products. Surely this isn't n-tier is it - i.e. executing business logic client side? I'm from an ASP.Net background and would normally develop a business tier (WCF service), exposing an operation such as "GetProductsForCategory(string categoryName)", that the client side would call. I'm a little confused as to why you would be executing a query on the client side.

Thanks in advance

Andy

RE: Building N-Tier business applications with WCF RIA Services – Part II

Zoltan Arvai — Wed, 07 Apr 2010 03:44:02 GMT

Lou: You have to add the [Include] attribute on top of the property (association) in the metadata class. And you also have to load it from the database / datasource and pass the data back aslo to the client side.

RAM: The short answer is yes, of course :)

RE: Building N-Tier business applications with WCF RIA Services – Part II

RAM — Tue, 06 Apr 2010 15:27:41 GMT

Hi,

I am new to .net and this posting was realy very informative , thankyou.

got a dump question though, in your example

NorthwindDomainContext ctx = new NorthwindDomainContext();

var query = from p in ctx.GetProductsQuery()

            where p.Categories.CategoryName == "Beverages"

            select p;

ctx.Load(query);

productDataGrid.ItemsSource = ctx.Products;

where does the filteration of data occurs server side or client side,

does the service return complete product table data to client and client applies the filter or is .Net smart enough to send the query to the server and apply the filter on server itself.

thanks

ram

RE: Building N-Tier business applications with WCF RIA Services – Part II

Lou — Thu, 25 Feb 2010 02:18:39 GMT

In this example Products are being included in the Category.

What if the Category has a related EntityCollection.

In my case I have Customers, Dogs and the Dogs have related vaccinations. I can select a customer and get the related dogs, however I can not get the related vaccinations, is there a way to get the data that is related to the related data?

RE: Building N-Tier business applications with WCF RIA Services – Part II

Radu Poenaru — Wed, 24 Feb 2010 13:59:40 GMT

Dear Trung Hoang,

Do you use MyISAM tables in your MySQL database?

I just created a MySQL database and default all new tables are created using MyISAM which, indeed, doesn't support Foreign keys.

But if you switch all tables to use the InnoDB engine instead, you'll be able to create foreign keys and use them in your RIA app with Entity Model.

I am in preparation of a article regarding RIA services, Silverlight and MySQL databases on my website, because I faced this issue on my own and I believe that it is very interesting to share this.

RE: Building N-Tier business applications with WCF RIA Services – Part II

middlevn — Thu, 28 Jan 2010 05:32:15 GMT

Thanks for the interesting post. I am using MySQL as backend database for my project. I wonder if there is any custom way to implement the so called "[Include]" so I can also load the related entities because, you know, MySQL don not support foreign keys or specifically associations in the Entity Model using in RIA.

Regards,

Trung Hoang