SilverlightShow: Data Validation in Silverlight Comments

RE: Data Validation in Silverlight 3

Hardik gheewala — Thu, 12 Aug 2010 16:13:59 GMT

Good solution.

This really helps me. Happy Codding!!!

RE: Data Validation in Silverlight 3

kiran dada — Fri, 12 Feb 2010 13:56:05 GMT

good

RE: Data Validation in Silverlight 3

panda — Sat, 30 Jan 2010 06:00:51 GMT

hello i am very new to silverlight and i have downloaded the source code and run with visual studio. it throws exceptions...."Unhandled by user code " .......thus i tried adding BindingValidationErrors. But it is not working does anyone knows of other ways to do validations ? it shouldn't be the way to throw exceptions in setter methods right ? if it is the way ... how do i actually handle the exception

RE: Data Validation in Silverlight 3

hack2root — Tue, 15 Dec 2009 14:00:49 GMT

Try my demo at

http://silverlightentityfw.codeplex.com

I've done validation support also

RE: Data Validation in Silverlight 3

jt — Tue, 14 Jul 2009 13:38:39 GMT

what would you suggest for auto generated classes?

RE: Data Validation in Silverlight 3

Tanmoy — Wed, 27 May 2009 00:28:55 GMT

Right Jon I agree with you. Its a bit problem to have it in auto generated classes.

RE: Data Validation in Silverlight 3

eye — Thu, 23 Apr 2009 10:23:11 GMT

Nice...and it works!

RE: Data Validation in Silverlight 3

Jon — Thu, 02 Apr 2009 19:11:08 GMT

I agree with the person that said that doing it this way is "dead wrong." I don't think the validation rules should be in the setters of the data model. One place where this becomes problematic is if you are using WCF proxy generated classes where the setters are generated for you. What about ValidationRule like in WPF? I hope Microsoft gets this right because I agree that a "major point in building line-of-business applications is the data validation." I don't think they have it totally right even in WPF, but, not having ValidationRule in Silverlight is worse.

RE: Data Validation in Silverlight 3

emil — Fri, 27 Mar 2009 02:35:30 GMT

You can attribute your class' properties, but if there is no one to process them (as with the case of the DataForm) they are just useless. The attributes are processed (read validated) out-of-the box by the DataForm. There is no built-in mechanism that will validate your data by the rules set in the attributes if you don't put your controls inside a DataForm. Of course, you can do that by yourself - write a control that takes those attributes in mind.

RE: Data Validation in Silverlight 3

McpGza — Thu, 26 Mar 2009 07:29:04 GMT

So do you say that these kind of validations (with Custom validation) will be alvailabe only for DataForm?

RE: Data Validation in Silverlight 3

emil — Thu, 26 Mar 2009 05:13:06 GMT

@McpGza, yes this is used when validating data inside a DataForm. We are preparing an article on this topic. Expect it tomorrow or in the beginning of the next week.

RE: Data Validation in Silverlight 3

McpGza — Wed, 25 Mar 2009 11:54:26 GMT

Hi,

But there is a new assembly and namespace (System.ComponentModel.DataAnnotations), probably desinged to validation. Do you know about it somtehing? How can it be used?

RE: Data Validation in Silverlight 3

emil — Wed, 25 Mar 2009 10:34:54 GMT

Martin, you are somewhat right, but that's the only built-in way to do data validation in that version. Throwing exceptions in proprties just to say 'hey that input is invalid' is not the pretties way to validate user input. I wish we have the opportunety to use IDataErrorInfo, but it seems we have to wait a bit longer.

RE: Data Validation in Silverlight 3

Martin Nyborg — Tue, 24 Mar 2009 16:19:23 GMT

I think that throwing exception for business rules is dead wrong.

RE: Data Validation in Silverlight 3

emil — Tue, 24 Mar 2009 03:50:09 GMT

@Bill, thanks, I fixed the typos.

@Memo, you can avoid that by applying [System.Diagnostics.DebuggerHidden()] attribute on the property. Notice that you may still get the VS Just-in-Time Debugger dialog asking you whether you want to debug it.

RE: Data Validation in Silverlight 3

memo — Mon, 23 Mar 2009 16:09:57 GMT

Visual studio keeps breaking when the exception is thrown. How do I avoid this behavior, yet have it still break for other exceptions?

RE: Data Validation in Silverlight 3

Bill — Sat, 21 Mar 2009 16:59:44 GMT

Thanks for the explanation. I like the way they have implemented the validation.

Minor point: You have a few typos third to last paragraph (...this triggerr is fired on PorpertyChanged event...).