Understand Lambda and anonomous function by reading code

Example code for anonomous function
Before
button1.Click += new EventHandler(button1_Click);
void button1_Click (object sender, EventArgs e)
{
textbox1.Text = DateTime.Now.ToShortDateString();
}

After Lambda Code:
button1.Click += (s, e) => { textbox1.Text = DateTime.Now.TosShortDateString(); } ;