Question

所以我尝试制作一个DropDownList。当我在aspx文件中执行它时它正在工作，但它在代码隐藏中不起作用。

    <asp:Panel ID="pnlChannel" runat="server">
<asp:SqlDataSource ID="sdsChannel" runat="server" ConnectionString="<%$ ConnectionStrings:Monitor_SQL %>" SelectCommand="SELECT * FROM TABLE"></asp:SqlDataSource>
<asp:DropDownList ID="ddlChannel" runat="server"  DataSourceID="sdsChannel"  AutoPostBack="True" DataTextField="Kanal"> 
</asp:DropDownList>
</asp:Panel>

然后我用C＃中的代码隐藏尝试了它：

   public Panel GetDropDownList()
{
    // Create drop down list and data source
    Panel pnlChannel = new Panel();
    pnlChannel.ID = "pnlChannel";
    DropDownList ddlChannel = new DropDownList();
    ddlChannel.ID = "ddlChannel";
    ListItem limDefault = new ListItem();
    SqlDataSource sdsChannel = new SqlDataSource();
    sdsChannel.ID = "sdsChannel";

    // Configure data source
    sdsChannel.ConnectionString = ConfigurationManager.ConnectionStrings["Monitor_SQL"].ConnectionString;
    sdsChannel.SelectCommand = "SELECT * From TABlE";


    // Configure drop down list
    ddlChannel.DataTextField = "Kanal";
    ddlChannel.DataValueField = "Kanal";
    ddlChannel.AppendDataBoundItems = true;
    ddlChannel.DataSourceID = "sdsChannel";
    ddlChannel.AutoPostBack = true;



    // Configure default list item
    limDefault.Selected = true;
    limDefault.Text = "Alle";
    limDefault.Value = "-1";

    //Add controls to static panel in footer
    ddlChannel.Items.Add(limDefault);
    pnlChannel.Controls.Add(ddlChannel);
    pnlChannel.Controls.Add(sdsChannel);
    return pnlChannel;
}

为什么不工作？ +我不会同时使用这两种，我想使用其中一种观点

Answer 1

根据您的评论：

如果在代码隐藏中执行此操作，则会有一个DropDownList，但列表中没有任何内容

您从未将控件绑定到数据：

ddlChannel.DataBind();

DropDownList不适用于代码隐藏C＃

1 个答案: