ASP.NET, Duplicate IDs, and Templated Control… Is there a more elegant way?

问题

My application interface provides end-user input to create markup, that of which I'm using a templated control for:

<me:MyControl>
  <TemplateA>
    I'm inside of an ITemplate
  </TemplateA>
  <TemplateB>
    So what, I am too. 
  </TemplateB>          
</me:MyControl>

I need to allow duplicate control ID's within web controls inside of these templates. Now I know I can't have a duplicate ID inside of a single template, but I can do this:

<me:MyControl>
  <TemplateA>
    <me:Textbox Id="ABC" />
  </TemplateA>
  <TemplateB>
    <me:Textbox Id="ABC" />
  </TemplateB>          
</me:MyControl>

What I want to do is instead of making the templates via property:

<TemplateContainer(GetType(HelloWorld))>
<PersistenceMode(PersistenceMode.InnerProperty)>
Public Property TemplateA() As ITemplate

Protected Overrides Sub CreateChildControls()

  If TemplateA IsNot Nothing Then TemplateA.InstantiateIn(Me)
  If TemplateB IsNot Nothing Then TemplateB.InstantiateIn(Me)
  MyBase.CreateChildControls()

End Sub

I want to make them by using a custom class type that Implements ITemplate. However, when I do this, I get errors about duplicate IDs:

Here's an example: https://msdn.microsoft.com/en-us/library/0e39s2ck.aspx

That way I can have properties and even override the control builder class to pull in custom controls without ugly markup.

So instead of this:

<me:MyControl>
  <TemplateA>
    <me:BaseControl Hello="World" Foo="Bar">
      More controls inside
    </me:BaseControl>
  </TemplateA>
</me:MyControl>

I can do this:

<me:MyControl>
  <TemplateA Hello="World" Foo="Bar">
    More controls inside        
  </TemplateA>
</me:MyControl>

So ultimately, more than anything this is all about solving the duplicate control ID issue, and I need the end user to have the ability to set this ID, so leaving out the IDs is out of the question. I want to be able to do this:

<me:MyControl>
  <TemplateA PropertyA="Hello" PropertyB="World">
    <asp:Textbox Id="Test" />        
  </TemplateA>
  <TemplateA PropertyA="Foo" PropertyB="Bar">
    <asp:Textbox Id="Test" />        
  </TemplateA>
</me:MyControl>

So, I need to be able to have duplicate IDs within their own instance of the control, which I know no other way to do this other than them being inside of a template, but I don't want templateA, templateB, etc. I need to be able to pass properties to these templates (building them as a class instead of an inner property, but still getting duplicate ID errors when I do it this way).

I wrote my examples in vb.net, but C# support is welcome. This is an asp.net question in general.

回答1:

Try xml linq

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Xml;
using System.Xml.Linq;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            string xmlHeader = "<?xml version=\"1.0\" encoding=\"utf-8\" ?>" +
                "<Root xmlns:me =\"abc\" xmlns:asp =\"def\"></Root>";
            XDocument doc = XDocument.Parse(xmlHeader);
            XElement root = (XElement)doc.FirstNode;
            XNamespace meNs = root.GetNamespaceOfPrefix("me");
            XNamespace aspNs = root.GetNamespaceOfPrefix("asp");

            XElement control = new XElement(meNs + "MyControl");
            root.Add(control);

            var inputs = new[] {
               new { PropertyA="Hello", PropertyB="World", Id="Test"},
               new { PropertyA="Foo", PropertyB="Bar", Id="Test"},
            };

            foreach (var input in inputs)
            {
                control.Add(new XElement("TemplateA", new object[] {
                    new XAttribute("PropertyA", input.PropertyA),
                    new XAttribute("PropertyB", input.PropertyB),
                    new XElement(aspNs + "Textbox", new XAttribute("Id", input.Id))
                 }));
            }
        }
    }
}

来源：https://stackoverflow.com/questions/39322405/asp-net-duplicate-ids-and-templated-control-is-there-a-more-elegant-way