Xamarin Picker selected item persisting on multiple pages

Question

Question: Perhaps the challenge could be stated this way: How do I bind a single property in a content page to a globally stored variable in Xamarin Forms?

Details: I am using the MVVM pattern. I have a navigation content page (1 of 3 such pages) with a Picker object which is populated dynamically from the collectionModel and said model is read/write. I am attempting to persist the SelectedItem (or index, whichever is most appropriate) thru all 3 content pages such that navigation from page to page shows the same item (from the user's perspective). How should I do this?

I can set the Picker.SelectedIndex manually in ContentPage_Appearing() event. I would much rather use binding.

If you are going to downvote, please explain why in the comments and give me the chance to make the question better. I cannot think of a good reason to downvote this question which has received multiple votes in both directions. — maplemale

Kevin Li Kevin Li · Accepted Answer · 2017-10-31T07:26:38

Follow these steps:

Create a static class, like this:

public static class DataClass
{
   public static int PickerSelectedIndex = 0;
}

Add the xmlns:local in ContentPage mark in each Content Page, like this:
```
xmlns:local="clr-namespace:DataPersist"
```

Binding the data for your controls in each page's Xaml, like this:

<Picker  x:Name="picker" SelectedIndex="{x:Static local:DataClass.PickerSelectedIndex}">

It works like this:

Xamarin Picker selected item persisting on multiple pages

1 Answers