[c#] How do you change the text in the Titlebar in Windows Forms?

public partial class Form1 : Form
{
    DateTime date = new DateTime();
    public Form1()
    {
        InitializeComponent();
}
    private void timer1_Tick(object sender, EventArgs e)
    {
        date = DateTime.Now;
        this.Text = "Date: "+date;
    }
}

I was having some problems with inserting date and time into the name of the form. Finally found the error. I'm posting this in case anyone has the same problem and doesn't have to spend years googling solutions.