Hide GridView column Error: index was out of range must be non-negative and less than the size of the collection

hi all

I can not hide a column in gridview 

                    <asp:GridView ID="GridView1" runat="server" Width="100%" CellPadding="4" ForeColor="#333333" GridLines="None" OnRowDeleting="GridView1_RowDeleting">
                        <AlternatingRowStyle BackColor="White" />
                        <Columns>
                            <asp:TemplateField HeaderText="delete" ShowHeader="False">
                                <ItemTemplate>
                                    <asp:ImageButton ID="ImageButton1" runat="server" CausesValidation="False" CommandName="Delete" ImageUrl="~/img/delete.png" Text="Delete" />
                                </ItemTemplate>
                            </asp:TemplateField>
                        </Columns>
                    </asp:GridView>

I use this code

gv1.Columns[0].Visible=True;

But show me this error

index was out of range.must be non-negative and less than the size of the collection .\r\nparameter name:index

thank you