ASP.NET - 模板字段下拉列表

Question

请参阅以下代码：

Protected Sub GVHistoricNames_RowUpdating(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.GridViewUpdateEventArgs) Handles GVHistoricNames.RowUpdating
            Try
                'Dim strUsercode As String = GVHistoricNames.Rows(e.RowIndex).Cells(2).Text
                Dim ddl As DropDownList = CType(GVHistoricNames.Rows(e.RowIndex).FindControl("ddlUsercode"), DropDownList)
                MsgBox(ddl.SelectedIndex)


            Catch ex As Exception
                 'I don't swallow exceptions
            Finally

            End Try
        End Sub

我正在尝试获取下拉列表的选定值。模板字段的定义如下：

<asp:TemplateField HeaderText="Usercode">
                 <ItemTemplate>
                <asp:DropDownList ID="ddlUsercode" runat="server" SelectedValue ='<%# Bind("Usercode") %>' DataTextField="Usercode" DataValueField="Usercode">
                </asp:DropDownList> 
                </ItemTemplate>
            </asp:TemplateField>

MsgBox（ddl.SelectedIndex）始终在以下位置打印空字符串：GVHistoricNames_RowUpdatinGVHistoricNames_RowUpdating。我在做什么？

Answer 1

检查您是否未在rowUpdating事件之前的页面生命周期中的某些位置绑定或填充下拉列表。确保根据需要使用not isPostback。检查那里的语法，因为我是C＃家伙！