XPath, XmlDataSource and selecting multiple elements of a node.

Question

Hey all, I'm trying to nest DataLists in an ASP.NET page and display data from a single XML file.  A sample of my XML file is as follows:

<Students>
 <Student id="1" birthday="04/20/1976">
  <Name>Jack</Name>
  <Pets>
   <Pet type="Dog">Missy</Pet>
   <Pet type="Dog">Monty</Pet>
   <Pet type="Cat">Felix</Pet>
  </Pets>
 </Student>
 <Student id="2" birthday="12/04/1995">
  <Name>Jill</Name>
  <Pets>
   <Pet type="Snake">Fido</Pet>
  </Pets>
 </Student>
 <Student id="3" birthday="05/04/1986">
  <Name>Jane</Name>
  <Pets>
   <Pet type="Cat">Fluffy</Pet>
   <Pet type="Cat">Sir. Winston of Canterbury, the Third</Pet>
   <Pet type="Cat">Envy</Pet>
   <Pet type="Rabbit">Snuggles</Pet>
  </Pets>
 </Student>
 <Student id="4" birthday="03/12/1985">
  <Name>John</Name>
  <Pets>
   <Pet type="Dog">Daisy</Pet>
   <Pet type="Dog">Duke</Pet>
  </Pets>
 </Student>
</Students>

In my XML Data Source, I call the single XML file without specifying an .XSL or XPath Expression.  Then, in my DataList (which references the XMLDataSource), I have the following markup:

  <asp:XmlDataSource ID="XmlDataSource1" runat="server" DataFile="~/App_Data/Students.xml">
  </asp:XmlDataSource>
  <asp:DataList ID="students" runat="server" DataSourceID="XmlDataSource1">
    <ItemTemplate>
      <h4>
        <%# XPath("Name") %>
        (<%# XPath("Name/../@id") %>)</h4>
      <p>
        <asp:DataList ID="pets" runat="server" DataSourceID="XmlDataSource1">
          <ItemTemplate>
            <%# XPath("Student[Name/../@id]/Pets/Pet") %> (<%# XPath("Student[Name/../@id]/Pets/Pet/@type")%>)</ItemTemplate>
        </asp:DataList>
      </p>
    </ItemTemplate>
  </asp:DataList>

The first part of my page displays correctly (where each student's name prints, along with the ID), but the nested DataList isn't populating with anything.  Does anyone have a suggestion on how I can get each pet to list beneath their respective student?

Answer 1

So, I read about something called the XPathSelect, which appears to let me set the DataSource to a specific node of my XML Document.  By using the following markup, I was able to get a single pet (the first one) to print beneath the students name.  Not quite what I was going for (since I want ALL to print), but I'm getting closer.  Will post back when I find more.

  <asp:XmlDataSource ID="XmlDataSource1" runat="server" DataFile="~/App_Data/Students.xml">
  </asp:XmlDataSource>
  <asp:DataList ID="DataList1" runat="server" DataSourceID="XmlDataSource1" >
    <ItemTemplate>
      <h4>
        <%# XPath("Name") %>
        (<%# XPath("Name/../@id") %>)</h4>
        
      <p>
 <asp:DataList ID="DataList2" runat="server" DataSource='<%# XPathSelect("Pets") %>'>
 <ItemTemplate>
  <%# XPath("Pet") %>
 </ItemTemplate>
 </asp:DataList>
      </p>
    </ItemTemplate>
  </asp:DataList>

Answer 2

Friendly bump.  This problem is still sitting on my plate.  :(

Answer 3

Rockstarter,

 

I guess you need to select all the students in the outter DataList by <%# XPathSelect("Student") %>, then in the inner DataList select all the pets of that student by <%# XPathSelect("Pets/Pet") %> and populate it by a Repeater.

Please try following code (Please adjust the asp stuff if needed, I know nothing about ASP.Net)

	<asp:XmlDataSource ID="XmlDataSource1" runat="server" DataFile="~/App_Data/Students.xml">
	</asp:XmlDataSource>
	<asp:DataList ID="students" runat="server" DataSourceID="XmlDataSource1">
 <ItemTemplate>
		<!-- select all the students -->
		<asp:Repeater id="Repeater1" runat="server" DataSource='<%# XPathSelect("Student") %>'>
			<ItemTemplate>	
				<h4>
					<%# XPath("Name") %>
					(<%# XPath("@id") %>)
				</h4>
				<p>
					<!-- select Pets under current student -->
					<asp:DataList ID="pets" runat="server" DataSource='<%# XPathSelect("Pets/Pet") %>'>
						<ItemTemplate>
							<%# XPath(".") %>
						</ItemTemplate>
					</asp:DataList>
				</p>
			</ItemTemplate>
		</asp:Repeater>
 </ItemTemplate>
 </asp:DataList>	

and also please refer to http://forums.asp.net/p/1630029/4197406.aspx which does exactly the same thing you want