gridview的正序逆序排列

private string ascOrDesc
{
get
{
if (ViewState["ascOrDesc"] == null) ViewState["ascOrDesc"] = "ASC";
return ViewState["ascOrDesc"].ToString();
}
set { ViewState["ascOrDesc"] = value; }
}


protected void gv_Sorting(object sender, ridViewSortEventArgs e)
{
this.SortBy = e.SortExpression;
if (this.ascOrDesc=="ASC")
{
this.ascOrDesc = "DESC";
}
else
{
this.ascOrDesc = "ASC";
}
BArticle barticle = new BArticle();
this.gv.DataSource = barticle.ListByArticleTypeID(0, "", 0, this.SortBy, this.ascOrDesc);
this.gv.DataBind();
}