DatePicker

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Xamarin.Forms;
namespace App2
{
    public partial class MainPage : ContentPage
    {
        bool dateselected = false;
        public MainPage()
        {
            InitializeComponent();
            dPicker.DateSelected += DPicker_DateSelected;
            dPicker.MaximumDate = DateTime.Now;
            dPicker.Unfocused += DPicker_Unfocused;

            btnclear.Clicked += Btnclear_Clicked;
        }
        private void DPicker_DateSelected(object sender, DateChangedEventArgs e)
        {
            dateselected = true;
            lblDate.Text = dPicker.Date.ToString();
        }
        private void DPicker_Unfocused(object sender, FocusEventArgs e)
        {
            if (dateselected == true)
            {
                lblDate.Text = dPicker.Date.ToString();
            }
            else
            {
                lblDate.Text = DateTime.Now.ToString();
            }
        }
        private void Btnclear_Clicked(object sender, EventArgs e)
        {
            lblDate.Text = "- - - - -";
        }
    }
}

<?xml version="1.0" encoding="utf-8" ?>

<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"

             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"

             xmlns:local="clr-namespace:App2"

             x:Class="App2.MainPage">

  <ContentPage.Content>

    <StackLayout>

      <DatePicker x:Name="dPicker" VerticalOptions="Center" HorizontalOptions="Center"/>

      <Label x:Name="lblDate"  FontSize="20" Text="- - - - -" VerticalOptions="Center" HorizontalOptions="Center"/>

        <Button x:Name="btnclear" Text="Clear" VerticalOptions="Center" HorizontalOptions="Center"/>

    </StackLayout>

  </ContentPage.Content>

 

</ContentPage>