Convert DateTime String to Datetime

Hi i have a value coming from external


Am getting string value (07/03/2011 12:00:00 AM ) and i want to convert to DateTime and update the Database.

At present am trying below methods but still no go...

Option 1:DateTime  myDateTime=System.Convert.ToDateTime(item.StartDate);

Option 2:

string strDateTime = sampledate; (when i use this "it shows Cannot implicitly convert type system.DateTime ? to String)
DateTime myDateTime = DateTime.Parse(strDateTime );

Please some one guide me what is the right way to convert