从REST API调用获取xml节点值

Question

We are trying to get the Url from the entries of the list below by using c#.

<?xml version="1.0" encoding="utf-8" ?>
<feed xml:base="https://thomasmorestudent17.sharepoint.com/sites/devtest/_api/"  xmlns="http://www.w3.org/2005/Atom" xmlns:d="http://schemas.microsoft.com/ado/2007/08/dataservices" xmlns:m="http://schemas.microsoft.com/ado/2007/08/dataservices/metadata" xmlns:georss="http://www.georss.org/georss" xmlns:gml="http://www.opengis.net/gml">
    <id>b82076e4-3e36-4b09-bbed-3d14e0bf948f</id> 
    <title /> 
    <updated>2014-03-19T10:21:14Z</updated> 
- <entry>
    <id>https://thomasmorestudent17.sharepoint.com/sites/devtest/_api/Web/Lists(guid'ab8811c5-0d39-457c-8fd1-c15a45c78f89')/files('Aanleiding en achtergrond van het project.docx')</id> 
    <category term="MS.FileServices.File" scheme="http://schemas.microsoft.com/ado/2007/08/dataservices/scheme" /> 
    <link rel="edit" href="Web/Lists(guid'ab8811c5-0d39-457c-8fd1-c15a45c78f89')/files('Aanleiding%20en%20achtergrond%20van%20het%20project.docx')" /> 
    <title /> 
    <updated>2014-03-19T10:21:14Z</updated> 
  - <author>
       <name /> 
    </author>
  - <content type="application/xml">
    - <m:properties>
      - <d:CreatedBy m:type="MS.FileServices.UserInformation">
            <d:Id>9</d:Id> 
            <d:Name>Thomas More</d:Name> 
        </d:CreatedBy>
      <d:ETag>"{ECAEE072-FEDD-4FF6-8A27-1EFF131B0064},1"</d:ETag> 
      <d:Id>Aanleiding en achtergrond van het project.docx</d:Id> 
      - <d:LastModifiedBy m:type="MS.FileServices.UserInformation">
            <d:Id>9</d:Id> 
            <d:Name>Thomas More</d:Name> 
        </d:LastModifiedBy>
        <d:Name>Aanleiding en achtergrond van het project.docx</d:Name> 
        <d:Size m:type="Edm.Int32">21616</d:Size> 
        <d:TimeCreated m:type="Edm.DateTime">2014-03-14T17:24:25Z</d:TimeCreated> 
        <d:TimeLastModified m:type="Edm.DateTime">2014-03-14T17:24:25Z</d:TimeLastModified> 
        <d:Url>/sites/devtest/Shared Documents/Aanleiding en achtergrond van het project.docx</d:Url> 
     </m:properties>
   </content>

We are however experiencing a problem with our code. When debugging, the url of the webRequest is correct but the itemList remains empty.

HttpWebRequest itemRequest = (HttpWebRequest)HttpWebRequest.Create(sharepointUrl.ToString() + "/_api/Web/lists(guid'" + listId + "')/files");
        itemRequest.Method = "GET";
        itemRequest.Accept = "application/atom+xml";
        itemRequest.ContentType = "application/atom+xml;type=entry";
        itemRequest.Headers.Add("Authorization", "Bearer " + accessToken);
        HttpWebResponse itemResponse = (HttpWebResponse)itemRequest.GetResponse();
        StreamReader itemReader = new StreamReader(itemResponse.GetResponseStream());

        var itemXml = new XmlDocument();
        itemXml.LoadXml(itemReader.ReadToEnd());

        var itemList = itemXml.SelectNodes("//atom:entry/atom:content/m:properties/d:Url", xmlnspm);

Edit:

Using the solution offered by Alex Thompson we have been able to narrow down the list of problems. After editing the code, I've been debugging my program and noticed that the XML below is all I get returned into my streamreader:

<feed xml:base="https://thomasmorestudent17.sharepoint.com/sites/devtest/_api/" xmlns="http://www.w3.org/2005/Atom" xmlns:d="http://schemas.microsoft.com/ado/2007/08/dataservices" xmlns:m="http://schemas.microsoft.com/ado/2007/08/dataservices/metadata" xmlns:georss="http://www.georss.org/georss" xmlns:gml="http://www.opengis.net/gml">
  <id>273fa8b2-b789-41d0-9edf-01eb12657299</id>
  <title />
  <updated>2014-03-20T09:58:18Z</updated>
  <author>
    <name />
  </author>
</feed>

This is undoubtedly not the XML it should return. If someone could point me in the right direction to what the cause of this problem may be, it would be greatly appreciated.I

Answer 1

You could do something like this:

private static readonly XNamespace d = "http://schemas.microsoft.com/ado/2007/08/dataservices";
private static readonly XNamespace m = "http://schemas.microsoft.com/ado/2007/08/dataservices/metadata";

...

XDocument doc = XDocument.Load(itemReader.ReadToEnd());
var itemsList = doc.Descendants(m + "properties").Descendants(d + "Url").Select(item => item.Value);

If you want to select multiple values into an object, you could do something like:

private static readonly XNamespace d = "http://schemas.microsoft.com/ado/2007/08/dataservices";
private static readonly XNamespace m = "http://schemas.microsoft.com/ado/2007/08/dataservices/metadata";

...

var itemsList doc.Descendants(m + "properties").Select(
    item => new Item()
    {
        Id = item.Element(d + "Id").Value,
        Name = item.Element(d + "Name").Value,
        Url = item.Element(d + "Url").Value
    });