Trying to get an editable GridView to work in a Web form -

here's the GridView definition

    asp:GridView ID="GV1" runat="server" AutoGenerateEditButton="True" 
        OnRowEditing = "GV1_RowEditing"
        OnRowUpdating = "GV1_RowUpdating"
        CellPadding="10" CellSpacing="10" BorderStyle="Solid" 
        HorizontalAlign="Center" Caption="DashBoard Configuration Settings" 
        CaptionAlign="Top">
        <EditRowStyle BackColor="#9999FF" />
    /asp:GridView>

Everything I've read says that in the GV1_RowEditing event all I need is

       protected void GV1_RowEditing(object sender, GridViewEditEventArgs e)
        {
            GV1.EditIndex = e.NewEditIndex;
            GV1.DataSource = GVSet;
            GV1.DataBind();
        }

And the Gird should show up with the input equivalents for the fields....However nothing shows after I click on the 'Edit' - no Grid, nada, nichts, nils

With the exception of one forum post, I did notice that most everyone explicitly defines the columns for the Grid. Is that required in order to do what I want to do?

Thanks