Develop Reference

System.ArgumentNullException when trying to access span with Xpath (C#)

So i've been trying to get a program working where I get info from google finance regarding different stock stats. So far I have not been able to get information out of spans. As of now I have hardcoded direct access to the apple stock.
Link to Apple stock: https://www.google.com/finance?q=NASDAQ%3AAAPL&ei=NgItWIG1GIftsAHCn4zIAg
What i can't understand is that I receive correct output when I trying it in the chrome console with the following command:
$x("//*[#id=\"appbar\"]//div//div//div//span");
This is my current code in Visual studio 2015 with Html Agility Pack installed(I suspect a fault in currDocNodeCompanyName):
class StockDataAccess
{
HtmlWeb web= new HtmlWeb();
private List<string> testList;
public void FindStock()
{
var histDoc = web.Load("https://www.google.com/finance/historical?q=NASDAQ%3AAAPL&ei=q9IsWNm4KZXjsAG-4I7oCA.html");
var histDocNode = histDoc.DocumentNode.SelectNodes("//*[#id=\"prices\"]//table//tr//td");
var currDoc = web.Load("https://www.google.com/finance?q=NASDAQ%3AAAPL&ei=CdcsWMjNCIe0swGd3oaYBA.html");
var currDocNodeCurrency = currDoc.DocumentNode.SelectNodes("//*[#id=\"ref_22144_elt\"]//div//div");
var currDocNodeCompanyName = currDoc.DocumentNode.SelectNodes("//*[#id=\"appbar\"]//div//div//div//span");
var histDocText = histDocNode.Select(node => node.InnerText);
var currDocCurrencyText = currDocNodeCurrency.Select(node => node.InnerText);
var currDocCompanyName = currDocNodeCompanyName.Select(node => node.InnerText);
List<String> result = new List<string>(histDocText.Take(6));
result.Add(currDocCurrencyText.First());
result.Add(currDocCompanyName.Take(2).ToString());
testList = result;
}
public List<String> ReturnStock()
{
return testList;
}
}
I have been trying the Xpath expression [text] and received an output that i can work with when using the chrome console but not in VS. I have also been experimenting with a foreach-loop, a few suggested it to others.
class StockDataAccess
{
HtmlWeb web= new HtmlWeb();
private List<string> testList;
public void FindStock()
{
///same as before
var currDoc = web.Load("https://www.google.com/finance?q=NASDAQ%3AAAPL&ei=CdcsWMjNCIe0swGd3oaYBA.html");
HtmlNodeCollection currDocNodeCompanyName = currDoc.DocumentNode.SelectNodes("//*[#id=\"appbar\"]//div//div//div//span");
///Same as before
List <string> blaList = new List<string>();
foreach (HtmlNode x in currDocNodeCompanyName)
{
blaList.Add(x.InnerText);
}
List<String> result = new List<string>(histDocText.Take(6));
result.Add(currDocCurrencyText.First());
result.Add(blaList[1]);
result.Add(blaList[2]);
testList = result;
}
public List<String> ReturnStock()
{
return testList;
}
}
I would really appreciate if anyone could point me in the right direction.

If you check the contents of currDoc.DocumentNode.InnerHtml you will notice that there is no element with the id "appbar", therefore the result is correct, since the xpath doesn't return anything.
I suspect that the html element you're trying to find is generated by a script (js for example), and that explains why you can see it on the browser and not on the HtmlDocument object, since HtmlAgilityPack does not render scripts, it only download and parse the raw source code.

How to get specific value from Web Service

I am using Global Weather Web Service in my asp.net application http://www.webservicex.net/globalweather.asmx?op=GetWeather.
The code works fine but I want to get only temperature to be displayed on label.
ServiceReference1.GlobalWeatherSoapClient client = new ServiceReference1.GlobalWeatherSoapClient("GlobalWeatherSoap");
string weather = client.GetWeather("Karachi Airport", "Pakistan");
Label1.Text = weather;
Label control is showing complete data provided by service (i.e Date, Time, Country and city name etc)

According to the link you have provided it returns that string in XML form.
So Use it as below:
var doc = XDocument.Parse(weather); //use .Load if you are pulling an xml file.
var location = doc.Root.Element("Location").Value;
var Temperature = doc.Root.Element("Temperature").Value;
Label1.Text = Temperature;
Just Like above you can get another values too e.g. DewPoint, RelativeHumidity etc
var DewPoint= doc.Root.Element("DewPoint").Value;
var RelativeHumidity = doc.Root.Element("RelativeHumidity ").Value;

You can get it like this also
string weather = client.GetWeather("Karachi Airport", "Pakistan");
XmlDocument xmlDoc = new XmlDocument();
xmlDoc.LoadXml(weather );
XmlNodeList elemlist = xmlDoc.GetElementsByTagName("Temperature");
string temp= elemlist[0].InnerXml;

Issue with Xml Project

I'm looking for some help.
I created an mp3 web service using visual studio c# and xml to store the data. I created a method that will allow a user to create a new playlist id to be stored to the xml document. I set my xml file as follows:
public class Service : System.Web.Services.WebService
{
//used as an access path to the xml file
string xmlFileName = "F:\\WebServices\\Mp3Server\\SongList.xml";
This is before any of the methods in my program.
My songlist.xml file is stored correctly and is the correct path from what I can see.
I currently had mp3 id's stored on the songlist.xml file is as follows:
<Playlist ID="123">
<Song Title="Bump">
<Artist>Ed Sheeran</Artist>
<Album>Asylum</Album>
<Year>2011</Year>
<Genre>Folk</Genre>
</Song>
<Song Title="3 AM">
<Artist>Matchbox Twenty</Artist>
<Album>Exile On Mainstream</Album>
<Year>2007</Year>
<Genre>Rock</Genre>
</Song>
</Playlist>
The code I wrote to create a new playlist id is as follows:
//creates a new playlist
[WebMethod]
public string createPlaylistName(string playlistID)
{
string errorMessage = "";
List<string> playlistNames = createPlaylist("/SongList//Playlist/ID");
if (playlistNames.Contains(playlistID))
{
errorMessage = "error! Id already exists";
}
else
{
string xpath = "/SongList/Playlist[#ID'" + playlistID + "']";
XmlDocument doc = new XmlDocument();
doc.Load(xmlFileName);
XmlElement root = doc.DocumentElement;
XmlNode playistNode = root.SelectSingleNode(xpath);
XmlElement playList = doc.CreateElement("Playlist");
XmlAttribute ID = doc.CreateAttribute("ID");
ID.Value = playlistID;
playList.Attributes.Append(ID);
playistNode.InsertAfter(playList, playistNode.LastChild);
doc.Save(xmlFileName);
errorMessage = "success";
}
return errorMessage;
}
But when I run the program, create a new playlist Id and invoke the command: it displays "page not found" webpage.
I can't figure out why the create method is crashing.
If anyone can give any advice, I would appreciate it very much.

Have you tried stepping through it? You'll find that it fails because your XPath expression isn't valid. Your concatenation creates an expression like this:
/SongList/Playlist[#ID'123']
Where it should be:
/SongList/Playlist[#ID='123']
I'm also not entirely sure the logic makes sense. You're checking that a playlist doesn't exist with that ID and then adding one. So how is your XPath expression supposed to return an element?
As an aside, you should probably look into LINQ to XML - it's a much nicer API, for example:
var doc = XDocument.Load(xmlFileName);
var playlist = doc.Descendants("Playlist")
.Single(e => (string)e.Attribute("ID") == "123");
playlist.AddAfterSelf(
new XElement("Playlist",
new XAttribute("ID", "456")
));

How to save directory list to xml file C#

I have looked all over for this. It could be me just typing the wrong thing in search I'm not sure. So, if you know a good tutorial or example of this please share. I'm trying to learn.
I have a C# Windows Form app I'm working on. I have information (movies in this case) saved in an XML file. I saved the xml file like this.
//Now we add new movie.
XmlElement nodRoot = doc.DocumentElement;
string allMyChildren = nodRoot.InnerText;
string capitalized = CultureInfo.CurrentCulture.TextInfo.ToTitleCase(movieEditNameTextbox.Text);
int indexLookForNewMake = allMyChildren.IndexOf(capitalized);
if (indexLookForNewMake >= 0)
{
MessageBox.Show("Movie is already saved.", "Error");
}
else
{
XmlElement el = doc.CreateElement("Name");
el.InnerText = capitalized;
doc.DocumentElement.AppendChild(el);
//Check if Year is really a Number.
if (movieEditYearTextbox.Text.All(Char.IsDigit))
{
//Remove ' cause it gives errors.
string capitalizedFixed = capitalized.Replace("'", "");
string capitalizedFinalFixed = capitalizedFixed.Replace("\"", "");
//Assign Attribute to each New one.
el.SetAttribute("Name", capitalizedFinalFixed);
el.SetAttribute("Type", movieEditTypeDropdown.Text);
el.SetAttribute("Year", movieEditYearTextbox.Text);
//Reset all fields, they don't need data now.
movieEditNameTextbox.Text = "";
movieEditYearTextbox.Text = "";
movieEditTypeDropdown.SelectedIndex = -1;
removeMovieTextbox.Text = "";
doc.Save("movie.xml");
label4.Text = "Movie Has been Edited";
loadXml();
}
else
{
//Error out. Year not a Number
MessageBox.Show("Check movie year. Seems it isn't a number.", "Error");
}
}
That all works fine. Now what I'm trying to do is make it where you can choose a directory, and it search the directory and sub directories and get file names and save them into the XML file.
I used this to try to accomplish this. It does pull the list. But it doesn't save it. It don't save the new information.
I can't use LINQ as it cause a confliction for some reason with other code.
DirectoryInfo dirCustom = new DirectoryInfo(#"D:\Video");
FileInfo[] filCustom;
filCustom = dirCustom.GetFiles("*",SearchOption.AllDirectories);
//Open XML File.
XmlDocument doc = new XmlDocument();
doc.Load("movie.xml");
XmlElement el = doc.CreateElement("Name");
string fulCustoms = filCustom.ToString();
foreach (FileInfo filFile in filCustom)
{
string capitalized = CultureInfo.CurrentCulture.TextInfo.ToTitleCase(filFile.Name);
string capitalizedFixed = capitalized.Replace("\"", "");
el.SetAttribute("Name", capitalizedFixed);
el.SetAttribute("Type", "EDIT TYPE");
el.SetAttribute("Year", "EDIT YEAR");
richTextBox1.AppendText(capitalizedFixed + "\r\n");
}
doc.Save("movie.xml");
label4.Text = "Movie Has been Edited";
loadXml();
Now, the richTextBox does display the information correctly but it don't save it.
The loadXml() is just my noobish way to refresh the datagridview.
I'm completely lost and don't know where to turn to. I know my coding is probarely horrible, lol. I'm new to this. This is my first more complex application I have worked on.
I can't think of anymore information that would help you understand what I mean. I hope you do.
Thank you so much for your help.

Not sure exactly what your LoadXML() method does but my only piece of advise with your issue is to change the way you are implementing this functionality.
Create an object called Movie
public class Movie
{
public Movie() {}
public String Title { get; set; }
blah... blah...
}
Then create a MovieList
public class MovieList : List<Movie> { }
Then implement the following 2 methods inside the MovieList.
public static void Serialize(String path, MovieList movieList)
{
XmlSerializer serializer = new XmlSerializer(typeof(MovieList));
using (StreamWriter streamWriter = new StreamWriter(path))
{
serializer.Serialize(streamWriter, movieList);
}
}
public static MovieList Deserialize(String path)
{
XmlSerializer serializer = new XmlSerializer(typeof(MovieList));
using (StreamReader streamReader = new StreamReader(path))
{
return (MovieList) serializer.Deserialize(streamReader);
}
}
Thats it... You now have your object serialized and you can retrieve the data to populate through binding or whatever other methods you choose.

Reading links in header using WebKit.NET

I am trying to figure out how to read header links using C#.NET. I want to get the edit link from Browser1 and put it in browser 2. My problem is that I can't figure out how to get at attributes, or even the link tags for that matter. Below is what I have now.
using System.XML.Linq;
...
string source = webKitBrowser1.DocumentText.ToString();
XDocument doc = new XDocument(XDocument.Parse(source));
webKitBrowser2.Navigate(doc.Element("link").Attribute("href").Value.ToString());
This would work except that xml is different than html, and right off the bat, it says that it was expecting "doctype" to be uppercase.

I finally figured it out, so I will post it for anyone who has the same question.
string site = webKitBrowser1.Url.Scheme + "://" + webKitBrowser1.Url.Authority;
WebKit.DOM.Document doc = webKitBrowser1.Document;
WebKit.DOM.NodeList links = doc.GetElementsByTagName("link");
WebKit.DOM.Element link;
string editlink = "none";
foreach (var item in links)
{
link = (WebKit.DOM.Element)item;
if (link.Attributes["rel"].NodeValue == "edit") { editlink = link.Attributes["href"].NodeValue; }
}
if (editlink != "none") { webKitBrowser2.Navigate(site + editlink); }