How do I put a dictionary key pair into a picker in xamarin forms and retrieve the key value from the picker?

Question

I have a xaml file where I put the picker in and a code behind to populate it. The code used below:

 Dictionary<string, int> list = new Dictionary<string, int>
            {
                { "Aqua", 6},
                { "Red", 1 },
                { "Silver", 2 },
                { "Teal", 3 },
                { "White", 4 },
                { "Yellow", 55 }
            };
            foreach (string item in list.Keys)
            {
                ddlPurpose.Items.Add(item);
            }

I am trying to get the value 55 when I select yellow but the only thing I get is 5. I am using this to get the selected value

var val1 = ddlPurpose.SelectedItem.ToString();
        var val2 = ddlPurpose.SelectedIndex;

Is it even possible to get the key value? Have looked into the BindablePicker but that didn't seem to work at all. Any help on this is greatly appreciated.

Answer 1

I guess what you meant to do is:

var pSelectedIndex = ddlPurpose.SelectedIndex;
var selectedKey = list.Values.ElementAt(pSelectedIndex);

I would recommend to get familiar with MVVM and in this specific case with Behaviors. I wrote a small example to demonstrate how it may look using MVVM:

public class PickerKeyValueTestViewModel : INotifyPropertyChanged
{
    static Dictionary<string, int> colors { get; } = new Dictionary<string, int>
        {
            { "Aqua", 6 },
            { "Red", 1 },
            { "Silver", 2 },
            { "Teal", 3 },
            { "White", 4 },
            { "Yellow", 55 }
        };

    public List<string> Colors { get; } = colors.Keys.ToList();

    public string SelectedColor { get; set; }

    public void OnSelectedColorChanged()
    {
        if (string.IsNullOrEmpty(SelectedColor)) return;
        var selectedValue = colors[SelectedColor];
    }

    // Using PropertyChanged.Fody
    public event PropertyChangedEventHandler PropertyChanged;
}

<ContentPage
    xmlns="http://xamarin.com/schemas/2014/forms"
    xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
    xmlns:local="clr-namespace:PickerKeyValueTest"
    x:Class="PickerKeyValueTest.PickerKeyValueTestPage">

    <ContentPage.BindingContext>
        <local:PickerKeyValueTestViewModel />
    </ContentPage.BindingContext>

    <StackLayout
        Margin="25">
        <Picker
            ItemsSource="{Binding Colors}"
            SelectedItem="{Binding SelectedColor}">

        </Picker>
    </StackLayout>
</ContentPage>