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reading elements based on dynamic names, c#, linq to xml, part II

Posted on 2012-03-29
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Last Modified: 2012-04-04
My xml file is set up like this:

<ord>
  <item>
    <sku>123456</sku>
  </item>
</ord>

With the help of kaufMed in another question, I am able to set up a configuration file to tell my application:  You can find item number at <ord><item><sku> then use that information to read my xml file dynamically.,

The code looks like this:

            string itemNo = @"//ord/item/sku";

            try
            {
                foreach (string XMLFileName in FilesIn)
                {
                    XDocument xDoc = XDocument.Load(XMLFileName);

                    foreach (var node in xDoc.XPathSelectElements(itemNo))
                        MessageBox.Show(node.Value);

which successfully returns all the skus in the file.


In reality, a given file will have more than one order, a given order will have more than one item, and descending from the item element, there are other elements besides sku that I need to read.

Is there any way I can enhance the above code to look at a specific occurence of the given node?  Is there any way I can, for example, recognize that I have three orders in the file, then read for each order individually (they do have an order number attribute not shown above, like this:  <ord> OrderNumber=998889), and then look at the item elements within that specific order?

Thanks in advance for any thoughts you might have.
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Question by:g_johnson
5 Comments
 
LVL 75

Expert Comment

by:käµfm³d 👽
ID: 37785410
Can you update your example XML to reflect this scenario?
0
 
LVL 21

Assisted Solution

by:masterpass
masterpass earned 100 total points
ID: 37785603
Have a look here

http://www.java2s.com/Code/CSharp/XML/ReadXMLnodeusingtheXMLpath.htm

using the [@nodeattribute='value'] along with the xpath can solve this issue!

Hope this helps!
0
 
LVL 10

Accepted Solution

by:
pfrancois earned 400 total points
ID: 37786078
When you compute
xDoc.XPathSelectElements(itemNo)

Open in new window

you get a list of nodes. You can store that as a variable and count how many nodes it has.

XmlNodeList nodelist = xDoc.XPathSelectElements(itemNo);
MessageBox.Show("Number of orders: " + nodelist.Count.ToString);
foreach (var node in nodelist) { ... ; }

Open in new window


Instead of parsing the whole list, you can restrict your XPath query to the specific order you want to retrieve. In that case, your XPathSelectElements call could look like
xDoc.XPathSelectElement("//ord/item/sku[2]")

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for selecting the second order. Caution: XPathSelectElement returns a node, XPathSelectElements returns a list of one or more nodes.

Selecting order number 998889 in the way described above happens with next XPath:
xDoc.XPathSelectElements("//ord[contains(text(), "OrderNumber=998889")]/item/sku")

Open in new window

but this is dangerous: OrderNumber=9988896666 will also be matched. If the XML file had tags like <order number="998889">, the XPath would be more robust and more beautiful:
xDoc.XPathSelectElements("//ord[@number="998889"]/item/sku")

Open in new window

but since you have no control on the XML structure, this is no more than wishful thinking.
0
 
LVL 4

Author Comment

by:g_johnson
ID: 37797358
I will be checking out all of the suggestions as soon as I can turn my attention back to this project.  Thanks for your input and patience.
0
 
LVL 4

Author Closing Comment

by:g_johnson
ID: 37808752
This helps tremendously and I think will solve my problem.  If not, I will use the looping technique shown by masterpass
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