C# async await example

AsyncAwait.cs

using System;
using System.Windows.Forms;
using System.Threading;
using System.Threading.Tasks;

class Program
{
	[STAThread]
	public static void Main()
	{
		Application.EnableVisualStyles();
        Application.SetCompatibleTextRenderingDefault(false);
        Application.Run(new Form1());
	}

	public class Form1: Form
	{
		public Form1()
		{				
			b1 = new Button();
			b1.Text = "Perform long operation";
			b1.Dock = DockStyle.Top;
			b1.Click +=	new EventHandler(B1_Click);
			Controls.Add(b1);
			
			b2 = new Button();
			b2.Text = "Show Message";
			b2.Dock = DockStyle.Top;
			b2.Click +=	new EventHandler(B2_Click);
			Controls.Add(b2);
			
			l = new Label();
			l.Text = "Wait";
			l.Dock = DockStyle.Bottom;
			Controls.Add(l);
		}
		
		Button b1;
		Button b2;
		Label l;
		
		private void B1_Click(object sender, EventArgs e)
		{
			DoLongOperation();
		}
		
		private void B2_Click(object sender, EventArgs e)
		{
			MessageBox.Show("message");
		}
		
		private async void DoLongOperation()
		{
			b1.Enabled = false;
			l.Text = "Doing...";
			
			var result = await Task<string>.Factory.StartNew(() =>
			{        
				Thread.Sleep(5000);
				return "Done";
			});
			
			l.Text = result;
			b1.Enabled = true;
		}
	}
}