自定义用户控件中的 ASP 嵌套标签

Question

我刚刚开始使用 C# 中的自定义用户控件，我想知道是否有任何示例说明如何编写一个接受嵌套标签的控件？

例如，当您创建asp:repeater 时，您可以为itemtemplate 添加嵌套标签。

Answer 1

前段时间我写了一封blog post 关于这个。简而言之，如果您有一个带有以下标记的控件：

<Abc:CustomControlUno runat="server" ID="Control1">
    <Children>
        <Abc:Control1Child IntegerProperty="1" />
    </Children>
</Abc:CustomControlUno>

您需要控件中的代码符合以下内容：

[ParseChildren(true)]
[PersistChildren(true)]
[ToolboxData("<{0}:CustomControlUno runat=server></{0}:CustomControlUno>")]
public class CustomControlUno : WebControl, INamingContainer
{
    private Control1ChildrenCollection _children;

    [PersistenceMode(PersistenceMode.InnerProperty)]
    [DesignerSerializationVisibility(DesignerSerializationVisibility.Content)]
    public Control1ChildrenCollection Children
    {
        get
        {
            if (_children == null)
            {
                _children = new Control1ChildrenCollection();
            }
            return _children;
        }
    }
}

public class Control1ChildrenCollection : List<Control1Child>
{
}

public class Control1Child
{
    public int IntegerProperty { get; set; }
}

Answer 2

我按照 Rob 的博客文章，做了一个稍微不同的控制。该控件是一个条件控件，实际上就像一个 if 子句：

<wc:PriceInfo runat="server" ID="PriceInfo">
    <IfDiscount>
        You don't have a discount.
    </IfDiscount>
    <IfNotDiscount>
        Lucky you, <b>you have a discount!</b>
    </IfNotDiscount>
</wc:PriceInfo>

然后我在代码中将控件的HasDiscount 属性设置为布尔值，它决定呈现哪个子句。

与 Rob 的解决方案的最大区别在于，控件中的子句确实可以包含任意 HTML/ASPX 代码。

这里是控件的代码：

using System.ComponentModel;
using System.Web.UI;
using System.Web.UI.WebControls;

namespace WebUtilities
{
    [ToolboxData("<{0}:PriceInfo runat=server></{0}:PriceInfo>")]
    public class PriceInfo : WebControl, INamingContainer
    {
        private readonly Control ifDiscountControl = new Control();
        private readonly Control ifNotDiscountControl = new Control();

        public bool HasDiscount { get; set; }

        [PersistenceMode(PersistenceMode.InnerProperty)]
        [DesignerSerializationVisibility(DesignerSerializationVisibility.Content)]
        public Control IfDiscount
        {
            get { return ifDiscountControl; }
        }

        [PersistenceMode(PersistenceMode.InnerProperty)]
        [DesignerSerializationVisibility(DesignerSerializationVisibility.Content)]
        public Control IfNotDiscount
        {
            get { return ifNotDiscountControl; }
        }

        public override void RenderControl(HtmlTextWriter writer)
        {
            if (HasDiscount)
                ifDiscountControl.RenderControl(writer);
            else
                ifNotDiscountControl.RenderControl(writer);
        }
    }
}

Answer 3

我最终得到了与Rob（wayback archive）@gudmundur-h 的答案非常相似的东西，但我使用了ITemplate 来摆脱那个烦人的“你不能在 X 标签之间放置内容”在使用中。我不完全确定实际需要什么，所以都在这里以防万一。

部分/用户控件标记：mycontrol.ascx

注意重要的位：plcChild1 和 plcChild2。

<!-- markup, controls, etc -->
<div class="shell">
    <!-- etc -->

    <!-- optional content with default, will map to `ChildContentOne` -->
    <asp:PlaceHolder ID="plcChild1" runat="server">
        Some default content in the first child.
        Will show this unless overwritten.
        Include HTML, controls, whatever.
    </asp:PlaceHolder>

    <!-- etc -->

    <!-- optional content, no default, will map to `ChildContentTwo` -->
    <asp:PlaceHolder ID="plcChild2" runat="server"></asp:PlaceHolder>

</div>

部分/用户控制代码隐藏：mycontrol.ascx.cs

[ParseChildren(true), PersistChildren(true)]
[ToolboxData(false /* don't care about drag-n-drop */)]
public partial class MyControlWithNestedContent: System.Web.UI.UserControl, INamingContainer {
    // expose properties as attributes, etc

    /// <summary>
    /// "attach" template to child controls
    /// </summary>
    /// <param name="template">the exposed markup "property"</param>
    /// <param name="control">the actual rendered control</param>
    protected virtual void attachContent(ITemplate template, Control control) {
        if(null != template) template.InstantiateIn(control);
    }

    [PersistenceMode(PersistenceMode.InnerProperty),
    DesignerSerializationVisibility(DesignerSerializationVisibility.Content)]
    public virtual ITemplate ChildContentOne { get; set; }

    [PersistenceMode(PersistenceMode.InnerProperty), DesignerSerializationVisibility(DesignerSerializationVisibility.Content)]
    public virtual ITemplate ChildContentTwo { get; set; }

    protected override void CreateChildControls() {
        // clear stuff, other setup, etc
        // needed?
        base.CreateChildControls();

        this.EnsureChildControls(); // cuz...we want them?

        // using the templates, set up the appropriate child controls
        attachContent(this.ChildContentOne, this.plcChild1);
        attachContent(this.ChildContentTwo, this.plcChild2);
    }
}

重要的位（？）：

• ParseChildren -- 这么多shows up?
• PersistChildren -- 所以动态创建的东西不会被重置？
• PersistenceMode(PersistenceMode.InnerProperty) -- 所以控件是parsed correctly
• DesignerSerializationVisibility(DesignerSerializationVisibility.Content) -- 同上？

控件用法

<%@ Register Src="~/App_Controls/MyStuff/mycontrol.ascx" TagPrefix="me" TagName="MyNestedControl" %>

<me:MyNestedControl SomeProperty="foo" SomethingElse="bar" runat="server" ID="meWhatever">
    <%-- omit `ChildContentOne` to use default --%>
    <ChildContentTwo>Stuff at the bottom! (not empty anymore)</ChildContentTwo>
</me:MyNestedControl>

Answer 4

我猜你正在寻找这样的东西？ http://msdn.microsoft.com/en-us/library/aa478964.aspx

您的标签已被删除或不可见，因此无法真正帮助您。