I'm building my first Xamarin MvvmCross application at the moment and I'm currently looking at validating user input to the view models.
Doing a lot of searching around everything (including the MvvmCross team) link to this plugin:
This plugin makes use of a very old version of MvvmCross v3. I have tried taking the code from this plugin and building it directly into my application Core project until I came across the Bindings breaking change. I then came to the conclusion that this plugin would actually require a complete re-write due to this in order to use the latest version of MvvmCross.
So I'm now a little stuck.
What is the currently recommended best approach for performing input validation in a view model?
EDIT: Add sample project on GitHub https://github.com/kiliman/mvx-samples/tree/master/MvxSamples.Validation
I use MVVM Validation Helpers http://www.nuget.org/packages/MvvmValidation/
It's a simple validation library that's easy to use. It's not tied to MvvmCross.
Here's how I use it, for example, in my SigninViewModel:
The nice part of it is that you can get Errors as a collection and bind them in your view. For Android, I set the Error property to the keyed Error message.
And here's what the validation looks like:
EDIT: show helper code