DateTime.ToString() format question

[Jimmy [Used-Disks]]

It seems that I cannot not pass "h", "hh", "H", or "HH" (but nothing else)
to the ToString() method of a DateTime. It raises an excaption: "Input
string was not in a correct format."

So my question is: How can I convert the date time to a string, if I only
want the hours to show?

Thanks -

 

[Jimmy [Used-Disks]]

Thanks Jay!