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XML to ListView

I have made a script in C# that should load data from a XML file into a ListView.
This is the XML file I used to test :
<?xml version="1.0" encoding="utf-8"?>
<Items>
<wordExample languageOne="Пока" languageTwo="Doei" languageThree="Goodbye" />
<wordExample languageOne="1" languageTwo="2" languageThree="3" />
<wordExample languageOne="4" languageTwo="5" languageThree="6" />
<wordExample languageOne="7" languageTwo="8" languageThree="9" />
</Items>
Now I get an error when I try to load the XMl into the ListView and I really don't know what it could be, this is actually the first time I try to use XML in C#.
This is the code used to load the XML into the ListView :
public void ImportXMLToListView(ListView listview)
{
DialogResult dr = OPEN_FILE_DIA.ShowDialog();
if (dr == DialogResult.OK)
{
XDocument doc = XDocument.Load(OPEN_FILE_DIA.FileName);
int counter = 0;
foreach (var dm in doc.Descendants("Items"))
{
string tmpOne = dm.Attribute("languageOne").Value;
string tmpTwo = dm.Attribute("languageTwo").Value;
string tmpThree = dm.Attribute("languageThree").Value;
counter++;
ListViewItem lvi;
lvi = new ListViewItem(tmpOne);
lvi.SubItems.Add(tmpTwo);
lvi.SubItems.Add(tmpThree);
listview.Items.Add(lvi);
}
}
}
Am I doing something wrong??
This is the error I get : (Object reference not set to an instance of an object.)
Please tell me what I do wrong I really try to understand :S

language attributes belongs to your wordExample items. You need doc.Descendants("wordExample")
foreach (var dm in doc.Descendants("wordExample"))
{
string tmpOne = (string)dm.Attribute("languageOne");
string tmpTwo = (string)dm.Attribute("languageTwo");
string tmpThree = (string)dm.Attribute("languageThree");
...
}
And you can use explicit cast instead of directly accessing Value property to avoid NullReferenceException.

C#: Creating XML document using Linq having not proper output?

I'm trying to create xml data from my data, creation was successfull but the output is bad how can I fix this issue?
Here is my code:
private void btnGenerate_Click(object sender, EventArgs e)
{
XElement xml = new XElement("Navigation",
new XElement("NavigationSets"));
foreach (DataRow row_navs in GetNavigationSets().Rows)
{
xml.Add(new XElement("NavigationName", row_navs["name"].ToString()));
foreach (DataRow row_sets in GetMenusInNavigationSetByNavigation(2).Rows)
{
if (int.Parse(row_sets["id"].ToString()) == int.Parse(row_navs["id"].ToString()))
{
foreach (DataRow row_menus in GetMenuById(int.Parse(row_sets["menu_id"].ToString())).Rows)
{
xml.Add(new XElement("MenuName", row_menus["name"].ToString()));
}
}
}
}
xml.Save("data.xml");
}
Im expecting an output like this
<?xml version="1.0" encoding="utf-8"?>
<Navigation>
<NavigationSets>
<NavigationName>
<MenuName></MenuName>
</NavigationName>
<NavigationSets/>
</Navigation>
In my current code my output is like this
<?xml version="1.0" encoding="utf-8"?>
<Navigation>
<NavigationSets/>
<NavigationName></NavigationName>
<MenuName></MenuName>
</Navigation>

To add to Jon Skeets answer,
You can also use
using System.Xml.Linq;
to loop through lists so it is all one statement,
new XElement("NavigationSets",
menus.Select(menu => new XElement("MenuName"))
)

Look at when you're adding elements:
xml.Add(new XElement("NavigationName", row_navs["name"].ToString()));
xml.Add(new XElement("MenuName", row_menus["name"].ToString()));
Where xml is this element:
XElement xml = new XElement("Navigation",
new XElement("NavigationSets"));
That means xml is the Navigation element, not the NavigationSets element. I suspect you want something like:
XElement outer = new XElement("Navigation");
XElement inner = new XElement("NavigationSets");
outer.Add(inner);
... then add to inner.

Reading XML file via XML nodes

I have this XML document I am trying to read in and insert into a data base. There will only ever be one GamePlay node however GamePlayStep may repeat so I have created a node list for this. For some reason GamePlayStep isn't receiving data. Here is the XML file:
<?xml version="1.0" encoding="utf-8" ?>
<GameData>
<GamePlay>
<type>add</type>
<GamePlayID>1</GamePlayID>
<ParticipantID>1</ParticipantID>
<GameID>1</GameID>
<GameDifficultyID>1</GameDifficultyID>
<Start>2012-08-06T12:19:33.154Z</Start>
<End>2012-08-06T12:30:33.154Z</End>
<Success>False</Success>
</GamePlay>
<GamePlayStep>
<GamePlayStepID>1</GamePlayStepID>
<Start>2012-08-06T12:19:33.154Z</Start>
<End>2012-08-06T12:30:33.154Z</End>
<SortOrder>1</SortOrder>
<Score>1</Score>
<hintUsed>True</hintUsed>
<GamePause>
<GamePauseID>1</GamePauseID>
<Start>2012-08-06T12:19:33.154Z</Start>
<End>2012-08-06T12:30:33.154Z</End>
<Order>1</Order>
<Duration>05:01</Duration>
</GamePause>
</GamePlayStep>
</GameData>
Here is my code:
public static void start()
{
string[] filePaths = Directory.GetFiles(System.Configuration.ConfigurationManager.ConnectionStrings["filePath"].ConnectionString);
List<GamePlay> gameObj = new List<GamePlay>();
List<GamePlayStep> gameStepObj = new List<GamePlayStep>();
foreach (string value in filePaths)
{
XmlDocument xd = new XmlDocument();
XmlNodeList GameSteps;
xd.Load(value);
XmlNode documentNode = xd.SelectSingleNode("/GameData/GamePlay");
GameSteps = xd.SelectNodes("/GameData/GamePlay/GamePlayStep");
GamePlay newGamePlay = new GamePlay();
newGamePlay.setType(Convert.ToString(documentNode.SelectSingleNode("type").InnerText));
newGamePlay.setGamePlayID(Convert.ToInt32(documentNode.SelectSingleNode("GamePlayID").InnerText));
newGamePlay.setParticipantID(Convert.ToInt32(documentNode.SelectSingleNode("ParticipantID").InnerText));
newGamePlay.setGameDifficultyID(Convert.ToInt32(documentNode.SelectSingleNode("GameDifficultyID").InnerText));
newGamePlay.setGameID(Convert.ToInt32(documentNode.SelectSingleNode("GameID").InnerText));
newGamePlay.setStartDateTime(Convert.ToDateTime(documentNode.SelectSingleNode("Start").InnerText));
newGamePlay.setEndDateTime(Convert.ToDateTime(documentNode.SelectSingleNode("End").InnerText));
newGamePlay.setSuccess(Convert.ToBoolean(documentNode.SelectSingleNode("Success").InnerText));
newGamePlay.setFile(value);
newGamePlay.addNewGamePlay();
foreach (XmlNode documentNode2 in GameSteps)
{
GamePlayStep newGamePlayStep = new GamePlayStep();
newGamePlayStep.setGamePlayStepID(Convert.ToInt32(documentNode2.SelectSingleNode("GamePlayStepID").InnerText));
newGamePlayStep.setGamePlayID(newGamePlay.getGamePlayID());
newGamePlayStep.setStartDateTime(Convert.ToDateTime(documentNode2.SelectSingleNode("Start").InnerText));
newGamePlayStep.setEndDateTime(Convert.ToDateTime(documentNode2.SelectSingleNode("End").InnerText));
newGamePlayStep.setOrderPlayed(Convert.ToInt32(documentNode2.SelectSingleNode("SortOrder").InnerText));
newGamePlayStep.setScore(Convert.ToInt32(documentNode2.SelectSingleNode("Score").InnerText));
newGamePlayStep.setHintUsed(Convert.ToBoolean(documentNode2.SelectSingleNode("hintUsed").InnerText));
newGamePlayStep.addNewGamePlayStep();
}
}
}
The GamePlay is filling the variables properly and inserting into the database however the GamePlaySteps in the NodeList are not. Does anyone see the problem or how I can improve this?
Thanks.

Your XPath for accessing the GamePlayStep is incorrect;
It should be:
GameSteps = xd.SelectNodes("/GameData/GamePlayStep");
As GamePlayStep is a child of GameData, not GamePlay, in your document.

Use LINQ2XML....its simple and cool
XElement doc=XElement.Load("yourXml");
newGamePlay.setType(doc.Descendants("GameData").Element("GamePlay").Element("type").Value);
....
foreach (Element eml in doc.Descendants("GameData").Elements("GamePlayStep"))
{
GamePlayStep newGamePlayStep = new GamePlayStep();
newGamePlayStep.setGamePlayStepID(Convert.ToInt32(elm.Element("GamePlayStepID").Value));
newGamePlayStep.setStartDateTime(Convert.ToDateTime(elm.Element("Start").Value));
.....
}

Parsing URL/web-service

I made a request to a third party API and it gives me the following response in XML.
<?xml version="1.0" ?>
<abc>
<xyz>
<code>-112</code>
<message>No such device</message>
</xyz>
</abc>
I read this using this code.
XmlDocument doc = new XmlDocument();
doc.Load("*** url ***");
XmlNode node = doc.SelectSingleNode("/abc/xyz");
string code = node.SelectSingleNode("code").InnerText;
string msg = node.SelectSingleNode("message").InnerText;
Response.Write("Code: " + code);
Response.Write("Message: "+ msg);
But I get an error on this line:
string code = node.SelectSingleNode("code").InnerText;
Error is:
Object reference not set to an instance of an object.

I changed the first line of your XML file into:
<?xml version="1.0"?>
to make it valid XML. With this change, your code works for me. Without the change, the parser throws an exception.

You can use LINQ to XML (if confortable):
XDocument doc = XDocument.Load(url);
var selectors = (from elements in doc.Elements("abc").Elements("xyz")
select elements).FirstOrDefault();
string code = selectors.Element("code").Value;
string msg = selectors.Element("message").Value;

As you've given it, there doesn't seem to be anything wrong with your code Edit : Your declaration is wrong, as svinja pointed out, and your xml won't even load into the XmlDocument.
However, I'm guessing that your xml is more complicated, and there is at least one namespace involved, which would cause the select to fail.
It isn't pretty, but what you can do is use namespace agnostic xpath to locate your nodes to avoid using a XmlNamespaceManager:
XmlDocument doc = new XmlDocument();
doc.Load("*** url ***");
XmlNode node = doc.SelectSingleNode("/*[local-name()='abc']/*[local-name()='xyz']");
string code = node.SelectSingleNode("*[local-name()='code']").InnerText;
string msg = node.SelectSingleNode("*[local-name()='message']").InnerText;
Response.Write("Code: " + code);
Response.Write("Message: "+ msg);
Edit - Elaboration
Your code works fine if you correct the declaration to <?xml version="1.0"?>
However, if you introduce namespaces into the mix, your code will fail unless you use namespace managers appropriately.
My agnostic xpath above will also parse an xml document like so:
<?xml version="1.0"?>
<abc xmlns="foo">
<xyz xmlns="bar">
<code xmlns="bas">-112</code>
<message xmlns="xyz">No such device</message>
</xyz>
</abc>

<?xml version="1.0">
<abc>
<xyz>
<code>-112</code>
<message> No such device </message>
</xyz>
</abc>
try to set a list:
XmlNodeList nodeList = root.SelectNodes("/abc/xyz");
then read all the nodes and get their text:
foreach(XmlNode node in nodeList)
{
if(node.Name == "code")
{
string code = node.InnerText;
}
else
if(node.Name == "message")
{
string msg = node.InnerText;
}
}

[XmlRoot("abc")]
public class Entity
{
[XmlElement("xyz")]
public SubEntity SubEntity { get; set; }
}
public class SubEntity
{
[XmlElement("code")]
public string Code { get; set; }
[XmlElement("message")]
public string Message { get; set; }
}
And use standart xmlserializer
var xmlSerializer = new XmlSerializer(typeof(Entity));
var result = xmlSerializer.Deserialize(new XmlTextReader("*** url ***"));
Response.Write("Code: " + result.SubEntity.Code);
Response.Write("Message: "+ result.SubEntity.Message);

Reading XML File with multiple NS

I am trying to read an XML feed to get the last post date. My xml looks like this:
<?xml version="1.0" encoding="UTF-8"?>
<rss version="2.0"
xmlns:content="http://purl.org/rss/1.0/modules/content/"
xmlns:wfw="http://wellformedweb.org/CommentAPI/"
xmlns:dc="http://purl.org/dc/elements/1.1/"
xmlns:atom="http://www.w3.org/2005/Atom"
xmlns:sy="http://purl.org/rss/1.0/modules/syndication/"
xmlns:slash="http://purl.org/rss/1.0/modules/slash/"
>
<channel>
<title>mysite</title>
<atom:link href="http://www.mysite.com/news/feed/" rel="self" type="application/rss+xml" />
<link>http://www.mysite.com/news</link>
<description>mysite</description>
<lastBuildDate>Tue, 22 Nov 2011 16:10:27 +0000</lastBuildDate>
<language>en</language>
<sy:updatePeriod>hourly</sy:updatePeriod>
<sy:updateFrequency>1</sy:updateFrequency>
<generator>http://wordpress.org/?v=3.0.4</generator>
<item>
<title>My first post!</title>
<link>http://www.mysite.com/news/2011/11/22/docstore-v2-released/</link>
<comments>http://www.mysite.com/news/2011/11/22/docstore-v2-released/#comments</comments>
<pubDate>Tue, 22 Nov 2011 16:10:27 +0000</pubDate>
<dc:creator>mysite</dc:creator>
<category><![CDATA[News]]></category>
<category><![CDATA[Promotions]]></category>
<category><![CDATA[docstore]]></category>
I didn't show all of the xml since it is rather long.
My method, so far, looks like this:
private void button1_Click(object sender, EventArgs e)
{
var XmlDoc = new XmlDocument();
// setup the XML namespace manager
var mgr = new XmlNamespaceManager(XmlDoc.NameTable);
// add the relevant namespaces to the XML namespace manager
mgr.AddNamespace("ns", "http://purl.org/rss/1.0/modules/content/");
var webClient = new WebClient();
var stream = new MemoryStream(webClient.DownloadData("http://www.mysite.com/news/feed/"));
XmlDoc.Load(stream);
// **USE** the XML anemspace in your XPath !!
XmlElement NodePath = (XmlElement)XmlDoc.SelectSingleNode("/ns:Response");
while (NodePath != null)
{
foreach (XmlNode Xml_Node in NodePath)
{
Console.WriteLine(Xml_Node.Name + ": " + Xml_Node.InnerText);
}
}
}
I'm having a problem with it telling me:
Namespace Manager or XsltContext needed. This query has a prefix,
variable, or user-defined function.
All I want to pull out of this xml code is the 'lastBuildDate'. I'm going in circles trying to get this code right.
Can someone tell me what I am doing wrong here?
Thank you!

You're not using the namespace manager.
// **USE** the XML anemspace in your XPath !!
XmlElement NodePath = (XmlElement)XmlDoc.SelectSingleNode("/ns:Response", mgr);

There is only one of the element you are going after, you could go directly to it using the XPath. That element is also in the default namespace, so you do not need to do anything special to get to it. What about:
var XPATH_BUILD_DATE="/rss/channel/lastBuildDate";
private void button1_Click(object sender, EventArgs e){
var xmlDoc = new XmlDocument();
var webClient = new WebClient();
var stream = new MemoryStream(webClient.DownloadData("http://www.mysite.com/news/feed/"));
xmlDoc.Load(stream);
XmlElement xmlNode = (XmlElement)xmlDoc.SelectSingleNode(XPATH_BUILD_DATE);
Console.WriteLine(xmlNode.Name + ": " + xmlNode.InnerText);
}
If you did however need to dig into elements in a different namespace, you can do that also with the XPath (example, getting the dc:creator:
/rss/channel/item[1]/*[local-name() = 'creator']