Question

我有一个生成的复选框列表，它是通过选择另一个复选框列表中的选项生成的：

CheckBoxList typefilter = new CheckBoxList { ID = "typefilter" + CheckBoxList1.Items[i].Text };
typefilter.RepeatDirection = RepeatDirection.Horizontal;
SortedList<int, string> filterValueList = new SortedList<int, string>();

typefilter.DataTextField = "Value";
typefilter.DataValueField = "Key";
typefilter.DataSource = getFilterOptions(int.Parse(CheckBoxList1.Items[i].Value));
typefilter.DataBind();

phSelectedItem.Controls.Add(typefilter);

现在的问题是，如果我想给我生成的复选框列表一个SelectedIndexChanged，我该怎么做呢？

编辑（使用建议的处理程序方法后，单击复选框将销毁整个复选框列表）：整个方法的代码

protected void cbl_RentalCategory_SelectedIndexChanged(object sender, EventArgs e)
{
    if (cbl_RentalCategory.Items.Count > 0)
    {
        Label selectedType = new Label { ID = "Title" };
        selectedType.Text = "<h3>Rental Items</h3>";

        phSelectedItem.Controls.Add(selectedType);
    }

    for (int i = 0; i < cbl_RentalCategory.Items.Count; i++)
    {
        if (cbl_RentalCategory.Items[i].Selected)
        {
            Label selectedType = new Label { ID = "selectedType" + cbl_RentalCategory.Items[i].Text };
            selectedType.Text = cbl_RentalCategory.Items[i].Text + "<br/>";

            phSelectedItem.Controls.Add(selectedType);

            CheckBoxList typefilter = new CheckBoxList { ID = "typefilter" + cbl_RentalCategory.Items[i].Text };
            typefilter.RepeatDirection = RepeatDirection.Horizontal;
            SortedList<int, string> filterValueList = new SortedList<int, string>();
            typefilter.AutoPostBack = true;
            typefilter.SelectedIndexChanged += typefilter_SelectedIndexChanged;
            typefilter.DataTextField = "Value";
            typefilter.DataValueField = "Key";
            typefilter.DataSource = getFilterOptions(int.Parse(cbl_RentalCategory.Items[i].Value));
            typefilter.DataBind();

            phSelectedItem.Controls.Add(typefilter);

            Label nextLine = new Label { ID = "nextLine" + cbl_RentalCategory.Items[i].Text };
            nextLine.Text = "<br/>";
            phSelectedItem.Controls.Add(nextLine);
        }
    }
}

getFilterOptions（）：

private SortedList<int, string> getFilterOptions(int typeID)
{
    SortedList<int, string> filterValueList = new SortedList<int, string>();

    string strConnectionString = ConfigurationManager.ConnectionStrings["SOMEDB"].ConnectionString;
    SqlConnection conn = new SqlConnection(strConnectionString);

    using (SqlCommand cmd = new SqlCommand("Select * FROM SOMEWHERE WHERE ID=@ID", conn))
    {
        conn.Open();
        cmd.Parameters.AddWithValue("@ID", typeID);
        cmd.ExecuteNonQuery();
        SqlDataReader reader = cmd.ExecuteReader();

        while (reader.Read())
        {
            filterValueList.Add(int.Parse(reader["ID"].ToString()), reader["InformationHeader"].ToString());
        }

        conn.Close();
    }

    return filterValueList;
}

Answer 1

以下是如何执行此操作。将Autopostback设置为true并创建selectedindexchanged方法。确保仅在页面加载时首次运行此代码。

if(!IsPostBack){
CheckBoxList typefilter = new CheckBoxList { ID = "typefilter" + CheckBoxList1.Items[i].Text };
typefilter.RepeatDirection = RepeatDirection.Horizontal;
SortedList<int, string> filterValueList = new SortedList<int, string>();
typefilter.AutoPostBack = true;
typefilter.SelectedIndexChanged += typefilter_SelectedIndexChanged;
typefilter.DataTextField = "Value";
typefilter.DataValueField = "Key";     
typefilter.DataSource = getFilterOptions(int.Parse(CheckBoxList1.Items[i].Value));
typefilter.DataBind();

phSelectedItem.Controls.Add(typefilter);
}

这里是你选择的索引更改方法

public void typefilter_SelectedIndexChanged(object sender, EventArgs e)
    {
        //your code
    }

Answer 2

如果我正确理解了您的问题，您需要动态创建复选框列表，这个动态生成的复选框列表也应该支持带有SelectedChange事件的AutoPostBack。

运行示例的步骤：

步骤1：在Visual Studio中创建一个简单的网站

步骤2：将下面的代码放在default.aspx.cs文件中，保留使用命名空间。

步骤3：将aspx代码放在default.aspx文件中

预期输出 复选框列表将出现默认页面加载。选择任何下拉项。代码将为每个选择生成单独的checkboxlist（子项）列表。选择单独生成的复选框列表中的任何项目，所选值将显示在屏幕上的标签中。

public partial class _Default : System.Web.UI.Page
{
string[] arrMasterDDLSelItem;
protected void Page_Load(object sender, EventArgs e)
{
    if (masterCheckBoxList.SelectedItem != null)
    {
        arrMasterDDLSelItem = new string[masterCheckBoxList.Items.Count];
        ListItem objListItem;
        for (int index = 0; index < masterCheckBoxList.Items.Count; index++)
        {
            objListItem = masterCheckBoxList.Items[index] as ListItem;
            if (objListItem.Selected)
                arrMasterDDLSelItem[index] = objListItem.Text;
        }
        if (arrMasterDDLSelItem.Count() > 0)
            RecreateControls(arrMasterDDLSelItem);
    }
}
protected void typefilter_SelectedIndexChanged(object sender, EventArgs e)
{
    CheckBoxList objCheckBoxList = sender as CheckBoxList;
    ListItem objListItem;
    string selectedItems=string.Empty;
    foreach (var item in objCheckBoxList.Items)
    {
        objListItem=item as ListItem;
        if (objListItem.Selected)
            selectedItems += " " + objListItem.Text + ",";
    }
    Label1.Text = selectedItems;
}

private SortedList<int, string> getFilterOptions(string selItem)
{
    SortedList<int, string> filterValueList = new SortedList<int, string>();
    for (int index = 0; index < 10; index++)
        filterValueList.Add(index, "SubItem -" + index.ToString() + " For " + selItem);
    return filterValueList;
}
private void RecreateControls(string[] masterSelectedItem)
{
    foreach (var item in masterSelectedItem)
    {
        if (item != null)
        {
            CheckBoxList typefilter = new CheckBoxList { ID = "typefilter" + item };
            typefilter.RepeatDirection = RepeatDirection.Horizontal;
            SortedList<int, string> filterValueList = new SortedList<int, string>();
            typefilter.AutoPostBack = true;
            typefilter.SelectedIndexChanged += new System.EventHandler(typefilter_SelectedIndexChanged);
            typefilter.DataTextField = "Value";
            typefilter.DataValueField = "Key";
            typefilter.DataSource = getFilterOptions(item);
            typefilter.DataBind();
            ContentPlaceHolder MainContent = (ContentPlaceHolder)this.Master.FindControl("MainContent");
            MainContent.Controls.Add(typefilter);
        }
    }
}

}

ASPX代码：

<%@ Page Title="Home Page" Language="C#" MasterPageFile="~/Site.master" AutoEventWireup="true"
    CodeFile="Default.aspx.cs" Inherits="_Default" %>

<asp:Content ID="HeaderContent" runat="server" ContentPlaceHolderID="HeadContent">
</asp:Content><asp:Content ID="BodyContent" runat="server" ContentPlaceHolderID="MainContent">
    <asp:CheckBoxList ID="masterCheckBoxList" runat="server" AutoPostBack="true">
        <asp:ListItem Text="Type-1" Value="1"></asp:ListItem>
        <asp:ListItem Text="Type-2" Value="2"></asp:ListItem>
        <asp:ListItem Text="Type-3" Value="3"></asp:ListItem>
    </asp:CheckBoxList>
    <asp:Label ID="Label1" runat="server" Text="Label"></asp:Label>
    <asp:Panel ID="pnlDropDownList" runat="server">
    </asp:Panel>
</asp:Content>

道歉代码可能具有在非常有限的时间内编写的优化范围，只能提供解决问题的方法。但经过上述细节测试和工作正常。注意此示例的参考取自 http://www.aspsnippets.com/Articles/Creating-Dynamic-DropDownList-Controls-in-ASP.Net.aspx

Answer 3

您是否有任何特定原因要从后面的代码创建CheckBoxList？

据我所知，您的要求是：显示一个主复选框列表（RentalCategory），并为每个复选框选择，显示一个标签（selectedType *）和另一个复选框列表（typefilter *）。

对于这种要求，我将使用在项目模板中具有selectedType Label和typefilter CheckBoxList的转发器控件，仅在设计时为typefilter分配SelectedIndexChanged事件处理程序。

从代码隐藏中，我将执行2个select语句（一个在master table-RentalCategory上，另一个在详细信息table-typefilter上，具有适当的过滤条件：其中@ID in（＆lt; RentalCategory list中所选复选框的ID＆gt;））一气呵成[假设：你没有太多的数据]

这将为我提供一个包含2个DataTables的DataSet。我将添加1个DataRelation并使用这个完整的DataSet与主复选框列表以及转发器（使用Row.GetChildRows或CreateChildView）绑定。

了解概念检查： http://support.microsoft.com/kb/306154 http://www.aspnettutorials.com/tutorials/controls/nestedrepeaters-csharp/

将SelectedIndexChanged添加到生成的checkboxlist

3 个答案: