SelectedIndexChanged不起作用!

Question

我的代码:

*的.aspx:

<asp:DropDownList ID="CountryList" CssClass="CountryList" runat="server" 
           OnSelectedIndexChanged="CountryList_SelectedIndexChanged" />

*.aspx.cs:

protected void Page_Load(object sender, EventArgs e)
{
   CountryList.SelectedIndexChanged += 
                          new EventHandler(CountryList_SelectedIndexChanged);
   ...  
}

protected void CountryList_SelectedIndexChanged(object sender, EventArgs e)
{
   LoadCityList(CountryList, CityList);
}

但这不起作用.

Answer 1

尝试设置AutoPostBack="true"此下拉列表:

<asp:DropDownList 
    ID="CountryList" 
    CssClass="CountryList" 
    runat="server" 
    OnSelectedIndexChanged="CountryList_SelectedIndexChanged"
    AutoPostBack="true"  
/>

此外,您无需在方法中手动连接事件处理程序Page_Load.它在编译webform时由ASP.NET自动完成:

protected void Page_Load(object sender, EventArgs e)
{
    ... 
}

protected void CountryList_SelectedIndexChanged(object sender, EventArgs e)
{
    LoadCityList(CountryList, CityList);
}