我是利用DropDownList_DataBinding事件来解决，给在DetailsView控件TemplateField中的DropDownList加上onDataBinding事件命令。然后在cs中处理这个事件就OK了。
DetailsView的aspx中代码如下（省略数据源代码）：
1 <asp:DetailsView ID="DetailsView1" DataKeyNames="ClassID" 2 runat="server" DataSourceID="SqlDataSource1" AutoGenerateRows="False" > 3 <Fields> 4 <asp:BoundField HeaderText="分类名称" DataField="ClassTitle" /> 5 <asp:TemplateField HeaderText="所属分类"> 6 <ItemTemplate> 7 <%#Eval("ParentTitle") %> 8 </ItemTemplate> 9 <EditItemTemplate> 10 <asp:DropDownList ID="ddlParent" runat="server" onDataBinding="ddlParent_DataBinding"> 11 </asp:DropDownList> 12 </EditItemTemplate> 13 </asp:TemplateField> 14 <asp:CommandField ShowEditButton="True" /> 15 </Fields> 16 </asp:DetailsView> cs文件中：1 protected void ddlParent_DataBinding(object sender, EventArgs e)2 { 3 //添加数据绑定代码4 //BindDropDownList((DropDownList)sender);5 }注意: 失败是因为调用FindControl方法太早了，你得在DetailsView的ItemCreated事件或者是PreRender事件里做才行。 protected void DetailsView1_PreRender(object sender, EventArgs e) { if (IsPostBack) { DetailsView detailsView = (DetailsView)sender; if (detailsView.CurrentMode == DetailsViewMode.Edit) { DropDownList dropDownList = (DropDownList)detailsView.FindControl("DropDownList1"); dropDownList.Items.Add(new ListItem("text", "value")); } } }