Question

I’m learning Web Forms, and I’m trying to convert an order form I had been building. I learned about XmlDataSource to source my XML file and Repeater to build a template to present the data, and all is mostly well.

First a sample of how my XML works, and then the problem:

<items>
    <item id="sheet-1">
        <name>Sheet the First</name>
        <price id="single" />
    </item>

    <item id="sheet-2">
        <name>Sheet the Second</name>
        <price id="double" />
    </item>
</items>

<costs>
    <cost id="single">.10</cost>
    <cost id="double">.20</cost>
    <cost id="triple">.30</cost>
</costs>

With my pre-Web Forms setup, I created a foreach loop to store all of the cost IDs and values in an array, and then when I looped through each item, I matched the price ID to the cost ID and then output the corresponding value.

I’d like to create the same effect within a Repeater. How I saw it in my head was something like this…

<p class="cost-line">
<%#XPath("../../costs/cost[@id='XPath("price/@id")']") %>
</p>

But I knew that that syntax was highly unlikely to work.

I’m not entirely sure how to word the question. I believe what I’m trying to do is use foreign keys with XPath and Repeaters. Is this possible? If not, what alternatives exist to get where I’m trying to go?

Answer 1

Assuming you are using XDocument and that you are binding this way :

yourRepeater.DataSource = yourXDocument.Root.Element("items").Elements("item").ToList();
yourRepeater.DataBind();

you can have a getCost method :

protected String getCost(XElement xel) 
  {
   return xel
            .Parent
            .Parent
            .Element("costs")
            .Elements("cost")
            .Where(x=>x.Attribute("id").Value==xel.Element("price").Attribute("id").Value)
            .First().Value;
  }

and then try something like this :

 <p class="cost-line">
    <%#this.getCost((XElement)Container.DataItem) %>
 </p>

hope this will help