A DateTimePicker isn't meant for display of date and time - it's meant for the user to enter information.
If you want to display the current date and time so that it changes every second:
0) Add a Label to your form
1) Add a Timer to your form.
2) Set it's Interval property to 500 - that's every half a second.
3) Set up a handler for its Tick event
4) In the handler, set the Label.Text property to the current time:
myLabel.Text = DateTime.Now.ToString();