OnSelectedIndexChanged事件未触发

Question

这是.aspx代码段.

                <tr>
                   <td></td>
                   <td class="sectionHeading">
                       Dashboard</td>
                    <td> Division &nbsp: &nbsp;&nbsp;
                        <asp:DropDownList ID="ddlDivisions" runat="server" `enter code     here`OnSelectedIndexChanged="ddlDivisions_SelectedIndexChanged" Width="152px">
                        </asp:DropDownList></td>
                </tr>

下面是我的数据绑定代码.它是从Page_Load()调用的

'Populate Diviions dropdown
    If Not IsPostBack Then
        ddlDivisions.DataSource = Divisions.Fetch().List
        ddlDivisions.DataTextField = "DivisionDesc"
        ddlDivisions.DataValueField = "DivisionID"
        ddlDivisions.SelectedValue = 3  'Divisioon All
        ddlDivisions.DataBind()
    End If

下面是我的事件处理程序......

  Protected Sub ddlDivisions_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles ddlDivisions.SelectedIndexChanged
        'Other code goes here
  End Sub

上面的事件处理程序没有被调用.作为我研究的一部分,我已经做了很多事情

1. 当数据不回发时,将数据绑定到下拉控件的数据源
   
2. 从工具箱添加了控件
   
3. 尝试在.aspx中添加事件处理程序.仍然没有奏效.

Answer 1

DropDownList的标记未指定AutoPostBack属性.这必须存在并设置为true(默认值为false):

<asp:DropDownList ID="ddlDivisions" runat="server" AutoPostBack="true" OnSelectedIndexChanged="ddlDivisions_SelectedIndexChanged" Width="152px">
</asp:DropDownList>