Develop Reference

XML to List in C#

This is the xml:
<Packages>
<Package>
<Id>1</Id>
<Prerequisites>
<Prerequisite>7</Prerequisite>
<Prerequisite>8</Prerequisite>
</Prerequisites>
</Package>
<Package>
<Id>2</Id>
.....
</Package>
....
</Packages>
And the list:
class lista
{
public int id {get; set;}
public List<int> pre{get;set;}
}
How can I add This xml pattern to a list of lista class and this is what i have got so far bot it only put one in the second list.
XDocument xdoc = XDocument.Load("Employee.xml");
var ListPckage =
(from item in xdoc.Descendants("Package")
orderby item.Element("Id").Value
select new
{
Id = item.Element("Id").Value,
Prerequisite = item.Element("Prerequisites").Element("Prerequisite").Value,
}).ToList();
foreach works for shoing them
foreach (var item in ListPckage)
{
Console.WriteLine(item.Id);
foreach (var item1 in ListPckage)
{
Console.WriteLine(item1.Prerequisites);
}
}

As John Sket mentioned in the comment to the question, one way to achieve that is to use Linq To Xml.
//string xcontent = #"xml content here";
//XDocument xdoc = XDocument.Parse(xcontent);
XDocument xdoc = XDocument.Load("FullPathToXml");
List<lista> resultlist = xdoc.Descendants("Package")
.Select(x=> new lista
{
id = Convert.ToInt32(x.Element("Id").Value),
pre = x.Descendants("Prerequisite").Select(y=>Convert.ToInt32(y.Value)).ToList()
})
.ToList();
But, i'd suggest to use XmlSerialization/XmlDeserialization.

First parse the XML to XDocument using XDocument.Parse to get XML in XDocument variable i.e.
var requiredXml = XDocument.Parse("Xml String here")
Then you can use LINQ to Xml (something like) as below:
//may be syntactic error but you can get an idea
var requiredList =
from element in requiredXml.Descandants("Package")
Select new lista { id = element.Element("ID").Value,
pre = element.Elements("Prerequisite").Select(x=> Convert.ToInt32(x.Value)).ToList() }

I'm confused by Linq XML query

Here is my XML sample. I want to select SystemSetting's value if ID = 123. But I can't figure out how. How can I select SystemSetting value if id's value equal to 123 ?
<?xml version="1.0" encoding="utf-8" ?>
<Private>
<System>
<ID>123</ID>
<NAME>Test</NAME>
<SystemSetting>128</SystemSetting>
<SystemSettingCS>127</SystemSettingCS>
</System>
<System>
<ID>124</ID>
<NAME>Test2</NAME>
<SystemSetting>128</SystemSetting>
<SystemSettingCS>127</SystemSettingCS>
</System>
<System>
<ID>0</ID>
<NAME>Test</NAME>
<SystemSetting>5</SystemSetting>
<SystemSettingCS>250</SystemSettingCS>
</System>
</Private>
Here's what I tried:
var doc = XDocument.Load(Application.StartupPath+ #"\Settings.xml");
var q = from Ana in doc.Descendants("Private")
from sistem in Ana.Elements("System")
where (int)sistem.Element("ID") == 123
from assetText in Sistem.Elements("System")
select assetText.Element("SystemSetting");
MessageBox.Show(q.ToString());
thnx for help.

I think you're making this more complicated than you need to. I think you just need:
var query = doc.Descendants("Private") // Or just doc.Root
.Elements("System")
.Where(x => (int) x.Element("ID") == 123)
.Select(x => x.Element("SystemSetting"))
.FirstOrDefault();
That will select the first matching element, admittedly. The type of query is then XElement; if you take off the FirstOrDefault() part, it will return an IEnumerable<XElement>, for all matching elements.
If you want just the value instead of the element, you can change the Select to:
.Select(x => (string) x.Element("SystemSetting"))
or
.Select(x => x.Element("SystemSetting").Value)
(The first will return null if there's no SystemSetting element; the second will throw an exception.)

Xpath (System.Xml.XPath) can really help here
var system = doc.XPathSelectElement("//System[ID[text()='123']]");
var val = system.Element("SystemSetting").Value;
or with a single line
var s = (string)doc.XPathSelectElement("//System[ID[text()='123']]/SystemSetting");

Your almost there
var xmlFile = XElement.Load(#"c:\\test.xml");
var query =
from e in xmlFile.Elements()
where e.Element("ID").Value == "123"
select e.Element("SystemSetting").Value;

var q = from s in doc.Descendants("System")
where (int)s.Element("ID") == 123
select (int)s.Element("SystemSetting");
And show result (q will have IEnumerable<int> type):
if (q.Any())
MessageBox.Show("SystemSettings = " + q.First());
else
MessageBox.Show("System not found");

Was a Linq question, but there is an alternate XPath approach, but the class defined below could work in either scenario.
Define a class to read from the parent System element:
public class XSystem
{
public XSystem(XElement xSystem) { self = xSystem; }
XElement self;
public int Id { get { return (int)self.Element("ID"); } }
public string Name { get { return self.Element("NAME").Value; } }
public int SystemSetting { get { return (int)self.Element("SystemSetting"); } }
public int SystemSettingCS { get { return (int)self.Element("SystemSettingCS"); } }
}
Then find your System element that has a child ID element of 123.
int id = 123;
string xpath = string.Format("//System[ID={0}", id);
XElement x = doc.XPathSelectElement(xpath);
Then plug it into the class:
XSystem system = new XSystem(x);
Then read the value you want:
int systemSetting = system.SystemSetting;
XPath is defined with using System.Xml.XPath;

Select statement for xdoc query

I am trying to add a sub category to Messages in my xml statement Is there a way I can do this GroupMessages -> Message -> GroupMessage :
var groups = xDoc.Descendants("Group")
.Select(n => new
{
GroupName = n.Element("GroupName").Value,
GroupHeader = n.Element("GroupHeader").Value,
TimeCreated = DateTime.Parse(n.Element("TimeAdded").Value),
Tags = n.Element("Tags").Value,
Messages = n.Element("GroupMessages").Value
//line above
})
.ToList();
dataGrid2.ItemsSource = groups;
In my method GroupMessages contains both MessageID and GroupMessage and it is listing both in my datagrid within the one container. So I tried this but it lists nothing:
Messages = n.Descendants("GroupMessages").Select(nd => nd.Element("GroupMessage").Value)
My XML looks like this:
<Group>
<TimeAdded>2012-04-27T10:23:50.7153613+01:00</TimeAdded>
<GroupName>Group</GroupName>
<GroupHeader>Header</GroupHeader>
<GroupMessages>
<Message>
<MessageID>1</MessageID>
<GroupMessage>Message</GroupMessage>
<MessageGroup/>
</Message>
</GroupMessages>
</Group>
I have also tried:
Messages = n.Descendants("GroupMessages").Select(nd => nd.Descendants("Message").Select(nde => nde.Element("GroupMessage").Value))
To no avail?
Update:
private void ListGroups_Click(object sender, RoutedEventArgs e)
{
string uriGroup = "http://localhost:8000/Service/Group";
XDocument xDoc = XDocument.Load(uriGroup);
var groups = xDoc.Descendants("Group")
.Select(n => new
{
GroupName = n.Element("GroupName").Value,
GroupHeader = n.Element("GroupHeader").Value,
TimeCreated = n.Element("TimeAdded").Value,
Tags = n.Element("Tags").Value,
Messages = n.Element("GroupMessages").Descendants("Message").Select(nd => new
{
//Id = nd.Element("MessageID").Value,
Message = nd.Element("GroupMessage").Value
}).FirstOrDefault()
})
.ToList();
dataGrid2.ItemsSource = groups;
}
Unfortunatley this method shows "Collection" inside the cell in the datagrid. If I try ToArray it will show an array message inside the cell. Is there a way to actually display the GroupMessage? Not sure how you set the child elements of a datagrid?

At the most basic level, you can do this to get a single message (the first one):
var groups = from grp in xDoc.Descendants("Group")
select new {
GroupName = grp.Element("GroupName").Value,
GroupHeader = grp.Element("GroupHeader").Value,
TimeCreated = DateTime.Parse(grp.Element("TimeAdded").Value),
Message = grp.Element("GroupMessages").Element("Message").Element("GroupMessage").Value
};
However, I assume that you want Messages to be a list of messages with both ID and Message. In that case, consider this:
var groups = from grp in xDoc.Descendants("Group")
select new {
GroupName = grp.Element("GroupName").Value,
GroupHeader = grp.Element("GroupHeader").Value,
TimeCreated = DateTime.Parse(grp.Element("TimeAdded").Value),
Messages = grp.Element("GroupMessages")
.Descendants("Message")
.Select(msg => new {
Id = msg.Element("MessageID").Value,
Message = msg.Element("GroupMessage").Value
}).ToList()
};
However, I strongly stress that all this usage of anonymous classes is just going to cause confusion. If you have a class for Group and Message then use those.
Note that the problem you're having is you're ignoring the XML structure and selecting random elements. To get the value out of a single element, you're going to need to select exactly that element, and ask for .Value. Selecting it's parent, or it's parent's parent (as you did) is not enough.

Try this:
var groups = xDoc.Elements("Group")
.Select(n => new
{
GroupName = n.Get("GroupName", string.Empty),
GroupHeader = n.Get("GroupHeader", string.Empty),
TimeCreated = n.Get("TimeAdded", DateTime.MinValue),
Tags = n.Get("Tags", string.Empty),
Messages = n.GetEnumerable("GroupMessages/Message", m => new
{
Id = m.Get("MessageID", 0),
Message = m.Get("GroupMessage", string.Empty),
Group = m.Get("MessageGroup", string.Empty)
}).ToArray()
})
.ToList();
I used the extension methods from here: http://searisen.com/xmllib/extensions.wiki
Get will handle null cases like your Tags node that doesn't exist in your xml, as well as the empty tag MessageGroup. You should use Elements() if the node you want is the child of the node you are referencing and not any descendant by that name.
I copied your xml into a root node to test it. It works on this xml:
<root>
<Group>
<TimeAdded>2012-04-27T10:23:50.7153613+01:00</TimeAdded>
<GroupName>Group</GroupName>
<GroupHeader>Header</GroupHeader>
<GroupMessages>
<Message>
<MessageID>1</MessageID>
<GroupMessage>Message</GroupMessage>
<MessageGroup/>
</Message>
</GroupMessages>
</Group>
<Group>
<TimeAdded>2012-04-27T10:23:50.7153613+01:00</TimeAdded>
<GroupName>Group</GroupName>
<GroupHeader>Header</GroupHeader>
<GroupMessages>
<Message>
<MessageID>1</MessageID>
<GroupMessage>Message</GroupMessage>
<MessageGroup/>
</Message>
</GroupMessages>
</Group>
</root>

Update XML file with Linq

I'm having trouble trying to update my xml file with a new value. I have a class Person, which only contains 2 strings, name and description. I populate this list and write it as an XML file. Then I populate a new list, which contains many of the same names, but some of them contains descriptions that the other list did not contain. How can I check if the name in the current XML file contains a value other than "no description", which is the default for "nothing"?
Part of the xml file:
<?xml version="1.0" encoding="utf-8"?>
<Names>
<Person ID="2">
<Name>Aaron</Name>
<Description>No description</Description>
</Person>
<Person ID="2">
<Name>Abdi</Name>
<Description>No description</Description>
</Person>
</Names>
And this is the method for writing the list to the xml file:
public static void SaveAllNames(List<Person> names)
{
XDocument data = XDocument.Load(#"xml\boys\Names.xml");
foreach (Person person in names)
{
XElement newPerson = new XElement("Person",
new XElement("Name", person.Name),
new XElement("Description", person.Description)
);
newPerson.SetAttributeValue("ID", GetNextAvailableID());
data.Element("Names").Add(newPerson);
}
data.Save(#"xml\boys\Names.xml");
}
In the foreach loop how do I check if the person's name is already there, and then check if the description is something other than "no description", and if it is, update it with the new information?

I'm not sure I understand properly what you want, but I'm assuming you want to update the description only when the name is already there and the description is currently No description (which you should probably change to an empty string, BTW).
You could put all the Persons into a Dictionary based by name:
var doc = …;
var persons = doc.Root.Elements()
.ToDictionary(x => (string)x.Element("Name"), x => x);
and then query it:
if (persons.ContainsKey(name))
{
var description = persons[name].Element("Description");
if (description.Value == "No description")
description.Value = newDescription;
}
That is, if you care about performance. If you don't, you don't need the dictionary:
var person = doc.Root.Elements("Person")
.SingleOrDefault(x => (string)x.Element("Name") == name);
if (person != null)
{
var description = person.Element("Description");
if (description.Value == "No description")
description.Value = newDescription;
}

You can use the Nodes-Method on XElement and check manually.
But i will advise you to use the XPathEvaluate-Extension Method
For XPath expression take a look at:
How to check if an element exists in the xml using xpath?

I think you could create a peoplelist which only contains people not in the xml.
like ↓
var containlist = (from p in data.Descendants("Name") select p.Value).ToList();
var result = (from p in peoplelist where !containlist.Contains(p.Name) select p).ToList();
so that , you would no need to change anything with your exist method ...
just call it after..
SaveAllNames(result);

Filtering your LINQ to XML query

I have the following:
XDocument xdoc = XDocument.Load("C:\\myfile.xml");
List<Tag> list = new List<Tag>();
foreach (var tag in xdoc.Descendants("META"))
{
string name = tag.Attribute("name").Value;
string value = tag.Element("value").Value;
list.Add(new Tag { Name = name, Value = value, Score = score, Key = key });
}
but I need to only get the META elements under the element ARTICLE.
Can I add this to the linq query somehow?
The xml looks similar to this:
<DOCUMENT>
<META name="aaa"/>
<ARTICLE>
<META name="bbb" value="708" score="0.58" key="6008"/>
</ARTICLE>
</DOCUMENT>
Thanks for any suggestions
In the end I need to do something like the following:
XDocument xdoc = XDocument.Load(tr);
var meta = from el in xdoc.Descendants("ARTICLE").Elements("META")
where (string) el.Attribute("name") == "RAW"
select el;
List<Tag> list = new List<Tag>();
foreach (var tag in meta)
{
string name = tag.Attribute("name").Value;
string value = tag.Attribute("value").Value;
string score = tag.Attribute("score").Value;
string key = tag.Attribute("key").Value;
list.Add(new Tag { Name = name, Value = value, Score = score, Key = key });
}
The reason for this is that I needed to match the attribute where the name was equal to RAW.
Please correct me if there's a better way to do this!

To find them anywhere in the document, use xdoc.Descendants("ARTICLE") to find all the ARTICLE elements, and then Elements("META") from there to find all the direct META children elements.
In addition, you can perform the projection and the conversion to a list in the same query:
var list = xdoc.Descendants("ARTICLE")
.Elements("META")
.Select(x => new Tag { Name = (string) x.Attribute("name"),
Value = (string) x.Attribute("value"),
Key = key })
.ToList();