如何创建使用 asp:ListItem 列表作为子控件的 ASP.NET 用户/服务器控件?

How to create ASP.NET user/server control that uses a list of asp:ListItem as child controls?(如何创建使用 asp:ListItem 列表作为子控件的 ASP.NET 用户/服务器控件?)

问题描述

我希望创建一个用户/服务器控件，该控件将使用以下内容创建:

I am looking to create a user/server control that will be created with something like the following:

<my:MyListControl runat="server">
   <asp:ListItem Text="Test1" Value="Test1" />
   <asp:ListItem Text="Test2" Value="Test2" />
</my:MyListControl>

我只是在这里寻找一个开始:文章或代码示例.

I am just looking for a start here: Articles or code samples.

我应该从哪个基类继承?要覆盖什么?

What base class should I inherit from? What to override?

可能如何自定义我的控件接受的子项(my:ListItem 而不是 asp:ListItem).

Possibly how to customize what sub items my control accepts (my:ListItem instead of asp:ListItem).

我要做的是为我网站的一小部分创建一个非常简单的面包屑控件.我已经将所有这些都与股票 ASP.NET 控件一起使用，但是这些项目是在代码中添加的，这意味着修复拼写错误或格式错误需要重新编译，这并不理想.

What I am looking to do is create a very simple bread crumb control for a small section of my site. I have it all working with stock ASP.NET controls, but the items are added in code, which means fixing a spelling mistake or formatting bug involves a recompile, which is not ideal.

这是我的代码，并在下面添加了 Josh 的建议:

Here's my code with the addition of Josh's suggestion below:

命名空间 MySite.Controls部分类面包屑继承用户控件

Namespace MySite.Controls Partial Class BreadCrumbs Inherits UserControl

    Private m_BreadCrumbs As New List(Of BreadCrumbItem)

    <PersistenceMode(PersistenceMode.InnerProperty)> _
    Public Property Items() As List(Of BreadCrumbItem)
        Get
            Return m_BreadCrumbs
        End Get
        Set(ByVal value As List(Of BreadCrumbItem))
            m_BreadCrumbs = value
        End Set
    End Property

    Private Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs) Handles MyBase.Load
        Bind()
    End Sub

    Private Sub Bind()
        lvCrumbs.DataSource = Items
        Me.DataBind()
    End Sub
End Class

Public Class BreadCrumbItem
    Private m_Text As String
    Public Property Text() As String
        Get
            Return m_Text
        End Get
        Set(ByVal value As String)
            m_Text = value
        End Set
    End Property

    Private m_Url As String
    Public Property Url() As String
        Get
            Return m_Url
        End Get
        Set(ByVal value As String)
            m_Url = value
        End Set
    End Property
End Class

结束命名空间

那么我的页面代码是这样的:

Then my page code looks like this:

<%@ Page Language="VB" AutoEventWireup="false" Inherits="MySite.MyPage" Title="My Page" Codebehind="MyPage.aspx.vb" %>
<%@ Register TagPrefix="my" Namespace="MySite.Controls" Assembly="MySite" %>
<my:BreadCrumbs ID="breadcrumbs" runat="server">
    <Items>
        <my:BreadCrumbItem Text="Another page" Url="AnotherPage.aspx" />
    </Items>
</my:BreadCrumbs>

推荐答案

您可以在用户控件的代码后面添加一个属性，例如:

You can add a property on a user control's code behind like:

[PersistenceMode(PersistenceMode.InnerProperty)]
public List<ListItem> Items
{
    get;
    set;
}

您的标记将是:

<my:MyListControl runat="server">
  <Items>
    <asp:ListItem/>
  </Items>
</my:myListControl>

为了使 ListItem 可以成为您自己的列表项(我建议这样做，而不是使用 asp.net.)您需要创建自己的类.

To make it so ListItem can be your own list item (Which I recommend doing as opposed to using asp.net.) You'll want to create your own class.

这是我使用的服务器控件的示例(我删除了很多噪音，因此这只是一个骨架):

Here's an example of a Server Control I use (I removed a lot of the noise as such this is just a skeleton):

   [ToolboxData("<{0}:Menubar runat=server></{0}:Menubar>")]
    [System.ComponentModel.DesignTimeVisible(false)]
    public class Menubar : WebControl, IPostBackEventHandler
    {

        private List<MenuItem> _menuItems = new List<MenuItem>();
        [PersistenceMode(PersistenceMode.InnerProperty)]
        public List<MenuItem> MenuItems
        {
            get
            {
                return _menuItems;
            }
        }

    }
    [ToolboxItem(false)]
    [ParseChildren(true, "MenuItems")]
    public class MenuItem
    {
        private string _clientClick;
        private List<MenuItem> _menuItems = new List<MenuItem>();

        [Localizable(true)]
        public string Title { get; set; }
        public string Href { get; set; }
        public string Id { get; set; }
        [PersistenceMode(PersistenceMode.InnerDefaultProperty)]
        public List<MenuItem> MenuItems
        {
            get { return _menuItems; }
            set { _menuItems = value; }
        }
    }

现在我可以这样使用:

<my:Menubar runat="server" ID="menuBar">
    <MenuItems>
        <my:MenuItem Title="Save" Href="javascript:saveItem(this);"  />
        <my:MenuItem Title="Print" Href="javascript:void(0);">
            <MenuItems>
                <my:MenuItem Title="Preview" Href=""/>
                <my:MenuItem Title="To Pdf" Href="javascript:"/>
            </MenuItems>
        </my:MenuItem>
    </MenuItems>
</my:Menubar>

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