Get Date on query string in asp.net c#

I am trying to send date format with dd/mm/yyyy in a hypelink field to another page , on page load for the b form iam trying t get this date but it is not working with me..

 

GridView Data:

and the another form :

 

editstarttxt.Text = Convert.ToDateTime(Request.QueryString["start_Date"]).ToString("dd/MM/yyyy") // the value that

 

i get is 01/11/0001 which is not the date ,

 

i also tried this but also an error occurs

 

DateTime.ParseExact(Request.QueryString["start_Date"].ToString(),"dd/MM/yyyy",null).ToString("yyyy-MM-dd"));

 

also didn't work