Get Date on query string in asp.net c#

Question

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:

<asp:HyperLinkField Text="Edit" Target="_blank" DataNavigateUrlFields="PackageId,StdId,CoachName,StdName,Sessions#,start_Date,Status,Remark"
DataNavigateUrlFormatString="EditAddPack.aspx?PackageId={0}&StdId={1}&CoachName={2}&StdName={3}&Sessions#={4}&start_Date={5:dd/MM/yyyy}&Status={6}&Remark={7}" />

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