SelectedIndexChanged不起作用！ [英] SelectedIndexChanged doesn't work!

问题描述

我的代码:

*.aspx:

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

*.aspx.cs:

*.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.

推荐答案

尝试设置 在此下拉列表上:

Try setting AutoPostBack="true" on this dropdown list:

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

此外，您无需手动连接Page_Load方法中的事件处理程序.它将在编译Web表单时由ASP.NET自动完成:

Also you don't need to manually wire-up the event handler in the Page_Load method. It will be automatically done by ASP.NET when it compiles the webform:

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

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

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