Async and Await - Asynchronous Programming

MainWindow.xaml

<Window x:Class="AsyncAwaitExample.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:AsyncAwaitExample"
        mc:Ignorable="d"
        Title="MainWindow" Height="350" Width="525">
    <StackPanel>
        <TextBlock Text="Enter number to sum:" HorizontalAlignment="Center" VerticalAlignment="Center" Margin="0,50,0,0"/>
        <TextBox Name="Input" Width="100" HorizontalAlignment="Center" VerticalAlignment="Center" Margin="0,10,0,0" />
        <Button Content="Calculate" HorizontalAlignment="Center" VerticalAlignment="Center" Width="75" Margin="0,10,0,0" Click="Button_Click"/>
        <TextBlock Text="The sum is:" HorizontalAlignment="Center" VerticalAlignment="Center" Margin="0,25,0,0"/>
        <TextBlock Name="Answer" Text="" HorizontalAlignment="Center" VerticalAlignment="Center" Margin="0,10,0,0"/>
    </StackPanel>
</Window>

MainWindow.xaml.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;

namespace AsyncAwaitExample
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
        }
        public async void DoSum(int number)
        {
            Console.WriteLine("Task started");
            var result = Calculate(number);
            Console.WriteLine("Task completed");
            if (!result.IsCompleted)
                await result;
            Answer.Text = result.Result.ToString();
            Console.WriteLine(string.Format("Answer is {0}", result.Result.ToString()));
        }
        public async Task<int> Calculate(int number)
        {
            var sum = 0;
            Task myTask = new Task(() =>
            {
                for (int i = 1; i <= number; i++)
                {
                    System.Threading.Thread.Sleep(1000);
                    sum += i;
                }
            });
            myTask.Start();
            await myTask;
            return sum;
        }

        private void Button_Click(object sender, RoutedEventArgs e)
        {
            if (!string.IsNullOrEmpty(Input.Text))
            {
                Console.WriteLine("Sum process started");
                var number = Convert.ToInt32(Input.Text);
                DoSum(number);
                Console.WriteLine("Sum process completed");
            }
        }
    }
}

Output -

Sum process started
Task started
Task completed
Sum process completed
Answer is 55