Using timers and DateTime.Now

Check out DateTime.ToString().  You can use textblock1.Text = DateTime.Now.ToString([format])

Particularly, check out the Standard format strings, and then the Custom Format strings.

If you are using ToString(), especially with DateTime objects, you will want to know that in different regions - date and time are in different formats.   Some have MM/DD/YYYY, some DD/MM/YYYY.  The link above has info about that too and how to deal with it.

Hope it helps.