using databinding in codebehind

Question

I have a page where I bind a command to a button. When I click it I calls a method where I get the data I want from an API.What if I don't want to only bind the data at the view but also use these data in code behind?! Lets say this is my view :

<ContentPage xmlns="http://xamarin.com/schemas/2014/forms" xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml" x:Class="HelloWorld.Pages.JohnDoePage" xmlns:local="clr-namespace:Xamarin.Forms.Maps;assembly=Xamarin.Forms.Pages" xmlns:vm="clr-namespace:HelloWorld.ViewModel;assembly=HelloWorld"> <StackLayout Padding="20, 10" HorizontalOptions="Center"> <Button Command="{Binding JohnDoe}" Text="Data about John Doe" /> </StackLayout> </ContentPage>

the code behihnd :

 Models.Info info; public JohnDoePage(Models.Info info) { InitializeComponent(); BindingContext = new InfoDetailsViewModel(info); this.info= info; // i want to use the data here //using the data }

the view model :

 Data _data; public Data Data { get { return _data; } set { if (value == _data) return; _data = value; OnPropertyChanged(); } } public ICommand JohnDoe { get { return new Command(async () => { var Dataa = await _apiServices.InfoAboutJohnDOe(); }); } }

and the service where I get the data I need is OK. I'm using the same viewmodel for binding different commands, and I don't know if this is possible by the way so I'm stuck. Any idea how can I use the data I get in the view code-behind?? Thanks in advance!!

Jason · Accepted Answer · 2018-01-07 21:50:48Z

1

why not just maintain a class level reference to your VM?

Models.Info info; InfoDetailsViewModel vm; public JohnDoePage(Models.Info info) { InitializeComponent(); vm = new InfoDetailsViewModel(info); BindingContext = vm; this.info= info; }

answered Jan 7, 2018 at 21:50

Jason

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3 Comments

John Over a year ago

yeah, ok..but what about the data? Because vm = new InfoDetailsViewModel(info); the info are another data which I get from another command.

Jason Over a year ago

Just expose a Data property in your VM, then you can access it from the code-behind

John Over a year ago

of course. I already did that but I didn't get the right reference of the model in code-behind. Thanks for the answer :)

Mark · Accepted Answer · 2018-01-07 21:52:00Z

Save the result of your Service call as a public property

public <TargetType> Dataa { get; set; }

and save the DataContext of your JohnDoePage as a member.

JohnDoePageViewModel dataContext = (JohnDoePageViewModel)this.DataContext;

Because then you are able to get the information from the ViewModel.

var data = dataContext.Dataa;

Does this help?

Hey Mark, a little to late, but I tried your solution and my app breaks. I think it happens because var data = dataContext.Dataa; this checks for the data before the button is tapped. Any idea on how to handle this?! :) @mark

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