Error :The DetailsView 'dv' fired event ModeChanging which wasn't handled.

[rote]

I can't get the Detailview in GridView to change to EditMode i keep getting
error :
:The DetailsView 'dv' fired event ModeChanging which wasn't handled.

In the ModeChanging event below i looked for the Detailview and added the
changeMode but still doesn't work

protected void dv_ModeChanging(object sender, DetailsViewModeEventArgs e)

{

if (e.NewMode == DetailsViewMode.Edit)

{

DetailsView gv = new DetailsView();

gv = (DetailsView)this.GridView1.FindControl("dv");

gv.ChangeMode(DetailsViewMode.Edit);

}

}

I have a DetailView dv in a GridView GridView1 template like so :
<asp:TemplateField>

<ItemTemplate>

<tr>

<td>

<td colspan="100%">

<div id="div<%# Eval("ID") %>"
style="display:none;position:relative;left:15px;OVERFLOW: auto;WIDTH:97%" >

<aspetailsView ID="dv" runat="server" Height="50px" Width="125px"

OnModeChanging="dv_ModeChanging">

<Fields>

<asp:TemplateField HeaderText="Name" SortExpression="Name">

<ItemTemplate>

<asp:Label ID="lblfname" Text='<%# Eval("Firstname") %>'
runat="server"></asp:Label>

</ItemTemplate>

<EditItemTemplate>

<asp:Label ID="lblsname" Text='<%# Eval("LastName") %>'
runat="server"></asp:Label>

</EditItemTemplate>

</asp:TemplateField>

<asp:CommandField ShowEditButton="True" />

</Fields>


</aspetailsView>

</div>


</td>

</tr>

</ItemTemplate>

</asp:TemplateField>

Any ideas what 'm doing wrong?
Thanks in advance.