How to make a simple number picker in Xamarin Forms and store selected value in a variable-CodePudding

I'm mostly new to coding - and I've been stuck on something which probably is very basic:

I'm trying to make a simple picker/drop down menu with numbers ranging from 1-30. And then: I'd like to store the selected number in a variable for use on several other C# pages of the app.

Does anyone know how to do this?

Thanks!

I've gone through a lot of tutorials - but most end up with bugs when I try to adjust the code. Also for many I'm not sure what to adjust.

CodePudding user response：

It's easy to achieve using MVVM pattern. For more information, you could refer to Xamarin.Forms Picker, Xamarin.Forms Data Binding and Part 5. From Data Bindings to MVVM.

I made a small demo for you.

In xaml file, define a Picker. Use the ItemsSource and SelectedItem property. Also we add a new button, the Command property of which is binded to SelectedCommand in the viewmodel.

<Picker x:Name="mypicker"
    ItemsSource="{Binding ItemCollection}"    
    SelectedItem="{Binding SelectedItem}"  />
<Button x:Name="mybutton"  Command="{Binding SelectedCommand}" BackgroundColor="Yellow" Text="button1" />

In MainPage.xaml.cs file, set the BindingContext:

this.BindingContext = new MainPageViewModel();

In MainPageViewModel.cs file:

public class MainPageViewModel
{
    int participantsturn = 1;
    public int SelectedItem { get; set; } // you can access the picker value through this property
    public ObservableCollection<int> ItemCollection { get; set; }

    public MainPageViewModel()
    {
        ItemCollection = new ObservableCollection<int>();
        CreateCollection();  //generate ItemSource for the picker
    }

    public Command SelectedCommand
    {
        get
        {
            return new Command(() =>
            {
                if (participantsturn == SelectedItem)
                {
                    Console.WriteLine("yes!!!!!!!!!!!");
                }else
                {
                    Console.WriteLine("no!!!!!!!!!!!!");
                }                 
            });
        }
    }
    private void CreateCollection()
    {
        var numList = Enumerable.Range(1, 30).ToList();
        ItemCollection = new ObservableCollection<int>(numList);
    }
}

Hope it works for you. If you still have any question, feel free to ask.