All tagged mvvm

Xamarin Forms MVVM - ObservableCollection

Eduardo Rosas Osorno
Xamarin

In the last few posts, I've been introducing the usage of certain interfaces that help use the MVVM pattern in Xamarin Forms applications. You can even find all that code and identify what I did in each post by switching branches in this repository.

In this post, I'll be talking about the ObservableCollection<T>, which isn't an interface, but does implement the INotifyCollectionChanged interface, which behaves similarly to the INotifyProeprtyChanged interface, and helps integrate notifications for when elements are added, deleted or updated within a collection.

Xamarin Forms MVVM - IValueConverter

Xamarin Forms MVVM - IValueConverter

Eduardo Rosas Osorno
Xamarin

In the previous posts, I have been creating a "calculator" using the MVVM architectural pattern, explaining the ICommand and INotifyPropertyChanged interfaces. I suggest you fork the code from this repository and take a look at the branches so you know what we added in each of those posts, or better yet, read through those posts before continuing with this one.

Because in this post we will take a look at the IValueConverter interface, and how it is a key interface that you can use when you have some information on the Model that has to be presented differently in the View. Say a DateTime that instead of displaying "2018-03-21T15:04:30.0000000-06:00" has to be displayed as "two days ago".

I will implement a very easy example that I hope will make it clear how you can use the interface.

Xamarin Forms MVVM - ICommand

Xamarin Forms MVVM - ICommand

Eduardo Rosas Osorno
Xamarin

In the previous post, we talked about the INotifyPropertyChanged, and I gave a small introduction about the MVVM architectural pattern, and how it will allow you to structure your code in a way that will make it easy to maintain, easy to scale and easy to reuse.

This post will be about the ICommand interface. If you have created Xamarin Forms applications before, this interface will help you replace all the event handlers you have in the code behind for button clicks (and other events) for code that you can now move over to your ViewModel.

Xamarin Forms MVVM - INotifyPropertyChanged

Xamarin Forms MVVM - INotifyPropertyChanged

Eduardo Rosas Osorno
Xamarin

The MVVM architectural pattern is widely used by a lot of XAML developers, which means that it is not only used by Xamarin developers but also by Windows, WPF, and other developers. This pattern guides the developer throughout structuring her code in a way that will make it much easier to maintain, scale, and reuse.

It is this last benefit the one that is most important, at least in early stages of development, to Xamarin developers, since that is what Xamarin is all about, let's then dive deep into how this pattern is used on a Xamarin Forms application, starting in this post with the INotifyPropertyChanged interface, one of the interfaces that will be of great use as we implement the MVVM architectural pattern.