Hi,
let me tell you steps to follow
First basics are first like write datacontrol and fill methods.
in the datacontrol you've to places code something like this.
<a href="nextpage.aspx?id=<%#Eval("id")%>">Update</a>
And then In nextpage you've to fill your second datacontrol with based on that querystring
if(Request.QueryString["id"]!=null)
{
datacontrol.datasource=getDataByID(request.QueryString["id"].toString());
datacontrol.databind();
}
After that you've to write update code in update button.
Try your own code for this
All the Best