sort expression always = "" in gridview... why?

[Smokey Grindle]

I'm trying desperatly to add a sort order arrow to my grid view and have
this code below ofr it... but when the code runs the girdview sortexpression
is always = "" never the sort name... why?! i want the image to show up on
only the column sorting on...

protected void GridView1_RowCr eated(object sender, GridViewRowEven tArgs e)
{
if (e.Row.RowType == DataControlRowT ype.Header)
{
foreach (TableCell tc in e.Row.Cells)
{
if (tc.HasControls ())
{
// search for the header link
LinkButton lnk = (LinkButton)tc. Controls[0];
if (lnk != null)
{
// inizialize a new image
System.Web.UI.W ebControls.Imag e img = new
System.Web.UI.W ebControls.Imag e();
// setting the dynamically URL of the image
img.ImageUrl = "~/img/ico_" + (GridView1.Sort Direction
== SortDirection.A scending ? "asc" : "desc") + ".gif";
// checking if the header link is the user's choice
if (GridView1.Sort Expression == lnk.CommandArgu ment)
{
// adding a space and the image to the header link
tc.Controls.Add (new LiteralControl( " "));
tc.Controls.Add (img);
}
}
}
}
}
} every time that executes the sort expression is = "" never the command
argument.....