Reloj digital

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace Reloj_digital_I
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}

private void Form1_Load(object sender, EventArgs e)
{
}




private void timer1_Tick(object sender, EventArgs e)
{
label1.Text = DateTime.Now.ToLongTimeString();
   label2.Text = DateTime.Now.ToShortDateString();
label3.Text = DateTime.Now.ToString("dddd");
}
}
}

https://msdn.microsoft.com/es-es/library/zdtaw1bw(v=vs.110).aspx

Recordar cambiar la propiedad del Timer (Enabled a true)