Asp.net Gridview error: Operator '-' is not defined for types 'Object' and 'Date'
<p>I used this code: <code>(Eval("RegDtTime")-DateTime.Now</code> to calculate the difference between Registered DateTime (is in a database) and <code>DateTime.now</code> in a <code>gridview</code>,  But get this error: <code>operator '-' is not defined for types 'Object' and 'Date'</code>. So what should I use instead?</p>