You need to use
RowDataBound
of GridView, something like:
protected void GridView_RowDataBound(Object sender, GridViewRowEventArgs e)
{
DataControlRowType rtype = e.Row.RowType;
if (rtype == DataControlRowType.DataRow && rtype != DataControlRowType.Footer
&& rtype != DataControlRowType.Separator && rtype != DataControlRowType.Header
&& rtype != DataControlRowType.Pager)
{
TextBox tb1 = (TextBox)e.Row.FindControl("myDate1");
TextBox tb2 = (TextBox)e.Row.FindControl("myDate2");
}
}