Pickers in Xamarin.Forms

public SamplePickerPage()
{
    Dictionary<string, Color>  _list = new Dictionary<string, Color> {
    { "Aqua", Color.Aqua }, { "Black", Color.Black }, { "Blue", Color.Blue },
    { "Yellow", Color.Yellow }, { "Gray", Color.Gray }, { "Green", Color.Green },
    { "Lime", Color.Lime }, { "Maroon", Color.Maroon }, { "Navy", Color.Navy },
    { "Olive", Color.Olive }, { "Purple", Color.Purple }, { "Red", Color.Red },
    { "Silver", Color.Silver }, { "Teal", Color.Teal }, { "White", Color.White }
    };

    //----------- Date Picker
    DatePicker _datePicker = new DatePicker {
        Format = "D",
    };

    //----------- Time Picker
    TimePicker _timePicker = new TimePicker {
        Time = new TimeSpan(17,0,0),
    };

    //----------- Item Picker
    Picker _itemPicker = new Picker {
        Title = "Item Picker",
        Items= {}
    };

    foreach ( string listItems in _list.Keys){
        //Adding Items to Item Picker.
        _itemPicker.Items.Add(listItems);
    }

    Content = new StackLayout
    {
        Padding = new Thickness(10, Device.OnPlatform(20, 0, 0), 10, 5),
        VerticalOptions=LayoutOptions.CenterAndExpand,
        Children = {
            _datePicker,
            _timePicker,
            _itemPicker
        }
    };
}