Forms Data Controls :: How To Show / Hide TemplateField Column Of GridView

I am trying to show/hide TemplateField of gridview but not getting it... here is ma sample aspx code

<asp:TemplateField HeaderText="ColumnA">
<ItemTemplate>
<asp:Label ID="lblTest" runat="server" Text=' <%# Eval("Test")>'></asp:Label>
</ItemTemplate>
</asp:TemplateField>

Now in server side i am trying to hide this column but failed !!

protected void gv_RowCreated(object sender, GridViewRowEventArgs e)
{
if (e.Row.RowType == DataControlRowType.Header || e.Row.RowType == DataControlRowType.DataRow)
gv.Columns[2].HeaderStyle.CssClass = "hiddenClass"; // here i am setting display:None using css class
}

how to show/hide TemplateField on server side