使用detailsview中自带的“新建”按纽无法出现编辑模式

点detaisview的“新建”按纽后，我在其ModeChanging事件中新建了个对象，绑定到此detailsview中，可detaisview上没出现编辑模式的界面。detaisview是绑定ilist数据源。
代码如下：
=======================================、
<Fields>
                        <asp:TemplateField HeaderText="车主编码">
                            <EditItemTemplate>
                                <asp:TextBox ID="TextBox1" runat="server" Text='<%# Bind("OwnerCode") %>'></asp:TextBox>
                            </EditItemTemplate>
                            <InsertItemTemplate>
                                <asp:TextBox ID="TextBox1" runat="server" Text='<%# Bind("OwnerCode") %>'></asp:TextBox>
                            </InsertItemTemplate>
                            <ItemTemplate>
                                <asp:Label ID="Label1" runat="server" Text='<%# Bind("OwnerCode") %>'></asp:Label>
                            </ItemTemplate>
                        </asp:TemplateField>
                        ......
                    </Fields>================================
cs代码
protected void DetailsView1_ModeChanging(object sender, DetailsViewModeEventArgs e)
        {
            if (e.NewMode == DetailsViewMode.Insert)
            {
                List<object> entities = new List<object>();
                EOwner entity = new EOwner();
                entity.OwnerCode = "xx";
                entities.Add(entity);
                //DetailsView1.in
                DetailsView1.DataSource = entities;
                DetailsView1.DataBind();
                DetailsView1.DefaultMode = DetailsViewMode.Insert;
                //DetailsView1.CurrentMode = DetailsViewMode.Insert;
            }