SelectedIndexChanged事件不会触发 [英] SelectedIndexChanged event doesn't fire

问题描述

我已将 AutoPostBack ="true" 属性添加到下拉列表中.这是行不通的.

I have added the AutoPostBack = "true" attribute to the drop down list. It doesn't work.

<asp:DropDownList CssClass="dropDownList" ID="ddlBusinessUnit" 
                  AutoPostBack="true" runat="server" Width="250px"   
                  OnSelectedIndexChanged="ddlBusinessUnit_SelectedIndexChanged">
</asp:DropDownList>

后面的代码:

Protected Sub ddlBusinessUnit_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs)
    Response.Write("Hello")
End

如何确保调用事件方法?

How can I ensure that the event method is called?

推荐答案

您是否在每次回发中都填充Dropdownlist?

Are you populating your Dropdownlist on every Postback?

使用

Use IsPostBack to check whether the page is loaded for the first time or not.

If Not IsPostBack Then
   BinDdlBusinessUnit()
End If

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