SilverlightShow: WCF RIA Services Part 6 - Validating Data Comments

Re: WCF RIA Services Part 6 - Validating Data

ylogico — Tue, 30 Aug 2011 15:56:33 GMT

Yes, I was talking about that :-(.

I'm using this to validate textboxes and I want to force a global validation.

Thanks anyway ;-)

Re: WCF RIA Services Part 6 - Validating Data

brian.noyes — Tue, 30 Aug 2011 15:55:08 GMT

If you are talking about data in the data grid, I do not know how to force it to display the validation errors all the time, it only shows them when the row goes into edit mode.

Re: WCF RIA Services Part 6 - Validating Data

ylogico — Tue, 30 Aug 2011 12:17:51 GMT

Thanks for your post!!

I'm using DataAnnotation in a Silverlight MVVM application for validation. My problem is that errors doesn't show up until user focus on that field and gets out of it. This can be a problem if user tries to "save" without using every required field for example.

Do you know how to force this Validation??

Thanks in advance!!!

RE: WCF RIA Services Part 6 - Validating Data

Brian Noyes — Tue, 03 May 2011 02:52:34 GMT

Hi Rahul,

Not an issue with RIA Services because all callbacks and Completed handlers are automatically marshaled to the UI thread.

RE: WCF RIA Services Part 6 - Validating Data

RahulMisra2000 — Mon, 02 May 2011 20:51:09 GMT

Brian,

Are there any cross-thread access issues when code in the callback tries to access the ViewModel properties that are bound to the UI controls because only the UI thread should be manipulating, directly or indirectly, the UI controls.

When working with WCF Data Services, I had to use the Deployment....Dispatcher to hook into the UI thread before accessing the UI controls.

Is this not an issue with WCF RIA ?

RE: WCF RIA Services Part 6 - Validating Data

alman — Wed, 13 Apr 2011 15:27:52 GMT

public class BookShelfService : LinqToEntitiesDomainService {
    [Insert]
    public void ShareBook(Book book) {
        ...
        AmazonService amazonService = new AmazonService();
        if (amazonService.IsValidASIN(book.ASIN) == false) {
            ValidationResult error =
                new ValidationResult("The specified Amazon ID did not resolve to an actual book.",
                                     new string[] { "ASIN" });
            throw new ValidationException(error, null, book);
        }
        ...
    }
}

RE: WCF RIA Services Part 6 - Validating Data

Robin — Tue, 29 Mar 2011 23:50:28 GMT

I'm new to Silverlight (old dog on ASP.net) so I have been struggling with my overall approach. I am now comfortable with my current project because you have helped me get a structure. The download was perfect for me. I am now enthused and working till 4am again - time passes so quickly doesn't it if only there was overtime?

Keep up the good work and if you are ever in London or in Hampshire UK I will stand you a beer or 2.

RE: WCF RIA Services Part 6 - Validating Data

Brian Noyes — Wed, 16 Mar 2011 23:26:59 GMT

Should be able to just add a ValidationResult to the collection of ValidationErrors on the entity base class and set the parameters to the ValidationResult constructor that identifies which properties it is associated with, like the CustomValidation method samples are doing for cross field validation.

RE: WCF RIA Services Part 6 - Validating Data

Kent Zhou — Wed, 16 Mar 2011 20:04:33 GMT

For async validation example, as this error is caused by property TotalTime, how to bind this validation to TotalTime, like annotation attribute bind to property in metadata class? In this way, user can see the redbox and message on TextBox for TotalTime.

RE: WCF RIA Services Part 6 - Validating Data

Jonathan ANTOINE aka Jmix90 — Fri, 22 Oct 2010 12:48:05 GMT

Hello,

This may interest you and/or your readers : [RIA Services] How to force the validation of my entities (and just the validation !) goo.gl/VPHV

Thx for the article by the way !

RE: WCF RIA Services Part 6 - Validating Data

Brian Noyes — Thu, 23 Sep 2010 19:40:11 GMT

Janni, it is also getting cropped and can't follow it as a result. Besides, it is getting a little too specific to your scenario to continue here. Please contact me directly via email (brian dot noyes at idesign.net) and I'll try to help you out.

Thanks, Brian

RE: WCF RIA Services Part 6 - Validating Data

iiordanov — Thu, 23 Sep 2010 18:30:10 GMT

Hi Janni,

You comment is reposted each time you refresh the page. Do not worry I will delete all repeated posts.

RE: WCF RIA Services Part 6 - Validating Data

Janni — Thu, 23 Sep 2010 18:26:52 GMT

Sorry, I don't know what happened here, why my post is displayed three times?

RE: WCF RIA Services Part 6 - Validating Data

Janni — Thu, 23 Sep 2010 18:07:33 GMT

adly the problems start earlier in my case.
This is my Update method on the server DomainService:

public void UpdateCdGroupDescriptions(cdGroupDescriptions currentcdGroupDescriptions)

{

if (currentcdGroupDescriptions.Title.ToUpper().Equals("BLABLA")) {

ValidationResult error = new ValidationResult("BLABLA wrong!", new string[] {"Title"});

throw new ValidationException(error, null, currentcdGroupDescriptions);

}

this.ObjectContext.cdGroupDescriptions.AttachAsModified

(currentcdGroupDescriptions,this.ChangeSet.GetOriginal(currentcdGroupDescriptions));

}

I am generating a ValidationError item for the property Title when it contains a specific string.
Then I throw a ValidationException containing this specific error.

On the client side the DomainContext SubmitChanges method looks like that (dummy code):

DataMgr.ArticleContext.SubmitChanges(submitOp => { var b = 10; }, null);


I am using a lambda which checks for errors in the SubmitOperation and displays the error. The problem isthat the code which handles this (ErrorHandler.DiplayError) is not called at all! 



When the server throws a ValidationException as I stated before on the client side I am getting a message box from Visual Studio Just-In-Time Debugger: 

"An unhandled exception('Unhandled Error in SIlverlight Application

Code: 4004

Category: ManagedRuntimeError

Message: System.ServiceModel.DomainServices.Client.DomainOperationException:

Submit operation failed validation. Please inspect Entity.ValidationErrors for

each Entity in EntitiesInError for more information.

...

...



This means that I have to somehow handle the exception before it gets rerouted my controls via their data binding? So I changed the code to this:



DataMgr.ArticleContext.SubmitChanges(submitOp => { submitOp.MarkErrorAsHandled(); }, null);
Now I am not getting the Exception warning dialog of my visual studio but nothing happens in my GUI. I told the system that I would handle the error by myself.

I tested my code with a TextBox which was bound via a twoway binding and no validation error popped up in my GUI.



I did not find a complete, working tutorial for this problem on the web.

RE: WCF RIA Services Part 6 - Validating Data

Brian Noyes — Thu, 23 Sep 2010 16:28:59 GMT

Hi Janni,

To a large degree, you don't have to do anything. When you throw that exception on the server, it gets associated inside the RIA Services stack with the entity it was passing to you for updates. When the update batch is completed, RIA Services returns results to the client. Those results include the validation errors that happened on the server for each entity, whether triggered by a validation attribute, or from throwing a ValidationException inside the update methods. On the client side, RIA Services implements the INotifyDataErrorInfo interface for each entity and puts those errors into the collection of errors and raises the ErrorsChanged event. Any bound properties on an entity should then requery by calling the GetErrors method and should display a validation error if the control supports it.

That being said, unfortunately the DataGrid only shows validation errors as far as I know if you are editing a row, so it will not show that validation error in the data grid unless you go in and start editing one of the cells for a row who's object has validation errors. If you have normal input controls like TextBox, you should see the validation error immediately. I looked around briefly while writing the article to try to find a way to get the DataGrid to display the validation errors when not in edit mode, but ran out of time and had to pass on that.

Hope that clarifies.

RE: WCF RIA Services Part 6 - Validating Data

Janni — Thu, 23 Sep 2010 11:14:19 GMT

Hi,

I am very intrerested in your example for server side validation.
Especially in the part were you throw a ValidationException in ValidateCustomerHours.
Your code looks like this:

if (!timeAllowed)

throw new ValidationException(

"You cannot enter more than 10 hours per billing cycle for this customer.");

This code is called in your DomainService in the method UpdateTask(Task currentTask).
Your example does not use this ValidationException so I prepared a little demo and threw
a ValidationException at the beginning of my UpdateXXX-method in my demo DomainService.

So far things work, I throw a ValidationException in my UpdateXXX-method in the DomainService and when the DomainContext.SubmitChanges submits an entity which triggers the ValidationException I am getting an exception on my client side.

Now how do I translate this specific exception into something that my datagrid or any control that uses bindings can use? How do I tell the corresponding cell in my datagrid or a textbox or whatever control to change its color to red and display the exception error?

How do I integrate this server side validation exception into something that shows up nicely on the client?

RE: WCF RIA Services Part 6 - Validating Data

Anand Subramanian — Tue, 31 Aug 2010 00:39:50 GMT

You just did an 9G in your tomcat

RE: WCF RIA Services Part 6 - Validating Data

Brian Noyes — Fri, 27 Aug 2010 02:52:18 GMT

Ooh, I love insightful readers! :) You caught me in some loose terminology. If it is truly a parent object, you would not be able to get to the object server side because it would not be passed down by RIA Services. However, depending on how you were using the object model and how you decorated it, you could use a Composition attribute on something that was logically a parent (i.e. a Customer property on an Task object) and then it could be passed down. But that would fundamentally modify the way you were managing that object in the domain service so you are not really treating it as a true parent, really more of a child at that point.

From a client side though, if the validation was only being used client side (not through the server metadata class for example), that Customer object would be populated still from the domain context setting up the whole object model on the client side and populating the related entity properties, so client side you could walk to the Parent through the related property on the child.

Hope that clears it up.

RE: WCF RIA Services Part 6 - Validating Data

eukal — Thu, 26 Aug 2010 13:02:14 GMT

You wrote "When the validity of one property’s value depends on the value of another property on the same object, or possibly the values of some of the child objects or a parent object, you can accommodate this fairly easily using custom validation"

How do you get the "parent object" (not "the same object") of a property from ValidationContext?