ASP.NET Web 窗体级联下拉列表 - 第二个列表的选定值在回发时重置
本文关键字:窗体 Web NET 级联 下拉列表 列表 第二个 ASP | 更新日期: 2023-09-27 18:33:28
我的问题可能微不足道,但我无法提醒自己该怎么做。我有 2 个下拉列表:
<span>
<asp:DropDownList ID="DDLEditWydzial" runat="server" DataSourceID="SqlListaWydzialow"
AutoPostBack="true" DataTextField="NazwaWydzialu" DataValueField="ident"
OnSelectedIndexChanged="OnWydzialChanged" EnableViewState="true">
</asp:DropDownList>
</span>
<span>
<span style="font-size: 8pt; font-family: Arial CE">
<asp:DropDownList ID="DDLEditSale" runat="server" EnableViewState="true"
AutoPostBack="true">
</asp:DropDownList>
</span>
</span>
第一个填充通过SqlDataSource
,第二个填充取决于前一个的选择。这是由事件处理程序完成的:
protected void OnWydzialChanged(object sender, EventArgs e)
{
SqlConnection conn = new SqlConnection(ConfigurationManager.ConnectionStrings["sworConnectionString"].ConnectionString);
conn.Open();
using (conn)
{
SqlCommand command = new SqlCommand("SELECT '-- wybierz salę --' as numer, -1 as ident UNION " +
"SELECT 'Sala ' + s.numer as numer, s.ident FROM sala s, sala_wydzial sw where s.czyus=0 and sw.id_wydzial="
+ DDLEditWydzial.SelectedValue + " and sw.id_sala = s.ident", conn);
SqlDataReader salaReader = command.ExecuteReader();
DDLEditSale.AppendDataBoundItems = true;
DDLEditSale.DataSource = salaReader;
DDLEditSale.DataTextField = "numer";
DDLEditSale.DataValueField = "ident";
DDLEditSale.DataBind();
conn.Close();
conn.Dispose();
}
}
然后,当我从第二个列表中选择值时,回发并在刷新列表包含数据之后,但第二个 DDL 中的任何内容都没有被选中。我已经检查了Page_Load,DDLEditSale是空的。
有什么想法吗?:)
编辑:OnInit和InitializeComponent代码(由ZedGraph生成):
override protected void OnInit(EventArgs e)
{
//
// CODEGEN: This call is required by the ASP.NET Web Form Designer.
//
InitializeComponent();
base.OnInit(e);
}
/// <summary>
/// Required method for Designer support - do not modify
/// the contents of this method with the code editor.
/// </summary>
private void InitializeComponent()
{
this.ZedGraphWeb1.RenderGraph += new ZedGraph.Web.ZedGraphWebControlEventHandler(this.OnRenderGraph);
}
我已经SqlDataSources
更改为ObjectDataSources
,它似乎有效,只需要在会话中保留wydzial
的id。当我有一点时间时,我会粘贴代码:)