How to compare string with DateTime ?

 I use a JavaScript calender, which will return the Date user selected
the format is "098/04/01"  
098 = year
04 = Month 
01 = Day
the column Type in DataBase is DateTime which 
the format is 2009/4/1 ?? 09:31:11
 
how do I use "098/04/01 " compare with  2009/4/1 ?? 09:31:11 ?
 
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I tried this way but not works...
 
 1 public DateTime DBDate(string Date) //this string Date is 098/04/01
2 {
3 int year = Int32.Parse(Date.Substring(0, 3)) + 1900;
4 string rtnYear = year.ToString() + Date.Substring(3, 6); ...