DropDownList的级联

Question

先绑定一个DropDownList 然后在第一个被选中时接着出来第二个的值

Answer 1

设置第一个DropDownList控件的AutoPostBack="true",然后处理其OnSelectedIndexChanged事件中，对第二个DropDownList进行数据绑定即可。

Answer 2

请参考：
http://hi.baidu.com/long2714/blog/item/e2aac0103368bf35dd540115.html

Answer 3

不过如果想实现无刷新效果，建议使用ajax来处理，你自己搜一下，很多的。

Answer 4

    <form id="form1" runat="server">
    <div>
        <asp:ScriptManager ID="ScriptManager1" runat="server">
        </asp:ScriptManager>
        <asp:UpdatePanel ID="UpdatePanel1" runat="server">
            <ContentTemplate>
                <div>
                    省份：<asp:DropDownList ID="ddlProvinceList" runat="server" AutoPostBack="true" 
                        onselectedindexchanged="ddlProvinceList_SelectedIndexChanged">
                    </asp:DropDownList>
                </div>
                <div>
                    城市：<asp:DropDownList ID="ddlCityList" runat="server">
                    </asp:DropDownList>
                </div>
            </ContentTemplate>
        </asp:UpdatePanel>
    </div>
    </form>public void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
            BindProvinces();
        }
    }    private void BindProvinces()
    {
        var list = new[] {
            new{ProvinceId="1",ProvinceName="湖南"},
            new{ProvinceId="2",ProvinceName="北京"},
            new{ProvinceId="3",ProvinceName="上海"},
        }.ToList();
        ddlProvinceList.DataSource = list;
        ddlProvinceList.DataTextField = "ProvinceName";
        ddlProvinceList.DataValueField = "ProvinceId";
        ddlProvinceList.DataBind();
    }
    protected void ddlProvinceList_SelectedIndexChanged(object sender, EventArgs e)
    {
        ddlCityList.Items.Clear();
        ddlCityList.Items.Add(new ListItem("请选择", "-1"));
        ddlCityList.Items.Add(new ListItem(ddlProvinceList.SelectedItem.Text, ddlProvinceList.SelectedItem.Value));
    }

Answer 5

1.先绑定第一个下拉框
2. 再绑定第二个下拉框 绑定时请传入第一个下拉框的编号
3.在OnSelectedIndexChanged 中调用第二个下拉框绑定事件并传入SelectedItem.Value

Answer 6

http://blog.csdn.net/xianfajushi/article/details/5928136