Date Format in ASP.Net GridView BouldField

My web is in asp.net+vb code and sql 2005 database. In a gridview i used to convert dateformat as dd/mm/yyyy (11 Jun 2011) format

convert (varchar, DTDOB,6) as [DTDOB]

when i use only DTDOB then date format is 6/11/2011 12:00:00 AM .(i can sort my grid on DTDOB and the date is correctly sorted)

when i use convert (varchar, DTDOB,6) as [DTDOB] then date format is 11 Jun 2011. (When i sort the date is sorted as per the day only.

eg 01 Nov 93,04 Nov 93,06 Nov 92,08 Jun 91,11 Dec 93 etc.