我创建了一个基本绑定两个下拉列表的服务器控件,一个用于国家和一个用于状态,并更新该国的selectedindexchanged事件的状态下拉列表。但是,它不会回发。任何想法为什么?在一个UpdatePanel包装他们(有呈现问题;也许是因为我没有一个页面引用?)积分ASP.NET/C#:DropDownList SelectedIndexChanged在服务器控件中未触发
这里是我有(有一些额外的数据访问的东西剥离出来):
public class StateProv : WebControl
{
public string SelectedCountry;
public string SelectedState;
private DropDownList ddlCountries = new DropDownList();
private DropDownList ddlStates = new DropDownList();
protected override void OnLoad(EventArgs e)
{
base.OnLoad(e);
IList<Country> countries = GetCountryList();
IList<State> states = new List<State>();
if (SelectedCountry != null && SelectedCountry != "")
{
states = GetStateList(GetCountryByShortName(SelectedCountry).CountryShortName);
}
else
{
states.Add(new State { CountryId = 0, Id = 0, StateLabelName = "No states available", StateLongName = "No states available", StateShortName = "" });
}
ddlCountries.DataSource = countries;
ddlCountries.DataTextField = "CountryLongName";
ddlCountries.DataValueField = "CountryShortName";
ddlCountries.SelectedIndexChanged += new EventHandler(ddlCountry_SelectedIndexChanged);
ddlCountries.AutoPostBack = true;
ddlStates.DataSource = states;
ddlStates.DataTextField = "StateLongName";
ddlStates.DataTextField = "StateShortName";
ddlCountries.DataBind();
ddlStates.DataBind();
if (!string.IsNullOrEmpty(SelectedCountry))
{
ddlCountries.SelectedValue = SelectedCountry;
if (!string.IsNullOrEmpty(SelectedState))
{
ddlStates.SelectedValue = SelectedState;
}
}
}
protected override void RenderContents(HtmlTextWriter output)
{
ddlCountries.RenderControl(output);
ddlStates.RenderControl(output);
}
private IList<Country> GetCountryList()
{
//return stuff
}
private IList<State> GetStateList(Country country)
{
//return stuff
}
private IList<State> GetStateList(string countryAbbrev)
{
Country country = GetCountryByShortName(countryAbbrev);
return GetStateList(country);
}
private Country GetCountryByShortName(string countryAbbrev)
{
IList<Country> list = dataAccess.RetrieveQuery<Country>();
//return stuff
}
private IList<State> GetAllStates()
{
//return stuff
}
protected void ddlCountry_SelectedIndexChanged(object sender, EventArgs e)
{
IList<State> states = GetStateList(GetCountryList()[((DropDownList)sender).SelectedIndex]);
ddlStates.DataSource = states;
ddlStates.DataBind();
}
}
编辑: Viewstate位于页面上,并且页面上的其他控件正确执行回发,但不是这样。
大概不能算作一个答案,但Ajax控件工具包提供你想要什么已经更新面板内:http://www.asp.net/AJAX/AjaxControlToolkit/Samples/CascadingDropDown/CascadingDropDown.aspx – Sean 2009-02-20 17:05:55
是的;不过,我已经宣誓永远不会。绝对垃圾IMO;实际上,我正在为我的项目构建一个替代品,因为我们只能让CCD控制与Web服务一起工作,这有其他含义。 – 2009-02-20 17:26:40