Here is my code and it keeps throwing exception that System.Xml.XmlException: Element 'Customer' was not found.And XML file pasted at bottom
public static List<Customer> GetCustomers()
{
// create the list
List<Customer> customers = new List<Customer>();
// create the XmlReaderSettings object
XmlReaderSettings settings = new XmlReaderSettings();
settings.IgnoreWhitespace = true;
settings.IgnoreComments = true;
// create the XmlReader object
XmlReader xmlIn = XmlReader.Create(path, settings);
// read past all nodes to the first Customer node
xmlIn.ReadToDescendant("Customers");
// create one Customer object for each Customer node
do
{
Customer c = new Customer();
xmlIn.ReadStartElement("Customer");
c.FirstName =
xmlIn.ReadElementContentAsString();
c.LastName =
xmlIn.ReadElementContentAsString();
c.Email =
xmlIn.ReadElementContentAsString();
customers.Add(c);
}
while (xmlIn.ReadToNextSibling("Customer"));
// close the XmlReader object
xmlIn.Close();
return customers;
Here is my XML and it clearly contains Element Customer
<?xml version="1.0" encoding="utf-8"?>
<Customers>
<Customer>
<FirstName>John</FirstName>
<LastName>Smith</LastName>
<Email>jsmith#gmail.com</Email>
</Customer>
<Customer>
<FirstName>Jane</FirstName>
<LastName>Doe</LastName>
<Email>janedoe#yahoo.com</Email>
</Customer>
</Customers>
From the docs for ReadStartElement(string):
Checks that the current content node is an element with the given Name and advances the reader to the next node.
When you've only called ReadToDescendant("Customers") the current node will be Customers, not Customer.
You can fix this either by changing that to ReadToDescendants("Customer") or by adding an extra call like that after the first one.
Do you really need to use XmlReader though? If you could read it using LINQ to XML your code would be much simpler:
return XDocument.Load(path)
.Root
.Elements("Customer")
.Select(x => new Customer {
FirstName = (string) x.Element("FirstName"),
LastName = (string) x.Element("LastName"),
Email = (string) x.Element("Email")
})
.ToList();
If you want to use ReadToDescendent, I think you need to read until the "Customer" node, like so:
// read past all nodes to the first Customer node
xmlIn.ReadToDescendant("Customer");
Related
I am parsing an XML fragment using LINQ to XML and I am finding one of the nodes I am selecting is missing the child nodes I am expecting.
Example XML
<CustomerList>
<Customer>
<LastName>Smith</LastName>
<FirstName>Todd</FirstName>
</Customer>
<Customer>
<LastName>Jones</LastName>
<FirstName>Fred</FirstName>
</Customer>
<Customer>Tom Jones</Customer> <!-- Missing child nodes -->
</CustomerList>
When I try and pull out the LastName and FirstName values I get the error Object reference not set to an instance of an object.
Parsing XML with LINQ
XDocument xml = XDocument.Parse(xmlResponse);
List<CustomerModel> nodeList = xml.Descendants("CustomerList")
.Descendants("Customer")
.Select(x => new CustomerModel
{
LastName = x.Element("LastName").Value,
FirstName = x.Element("FirstName").Value,
}).ToList<CustomerModel>();
In the cases where the <Customer> nodes do not have the <LastName> and <FirstName> nodes how do I skip over them or better yet not even select them in the first place?
What I was suggesting is:
XDocument xml = XDocument.Parse(xmlResponse);
List<CustomerModel> nodeList = xml.Descendants("CustomerList")
.Descendants("Customer")
.Where(x => x.Element("LastName") != null && x.Element("FirstName") != null)
.Select(x => new CustomerModel
{
LastName = x.Element("LastName").Value,
FirstName = x.Element("FirstName").Value,
}).ToList<CustomerModel>();
I have a xml file from which only specific nodes have to be removed. The node name will be given as input from the user. How to remove the specific nodes which have requested from the user?
<Customers>
<Customer>
<id>michle</id>
<address>newjersy</address>
</Customer>
<Customer>
<id>ann</id>
<address>canada</address>
</Customer>
</Customers>
I have tried
var customer = new XElement("customer",
from o in customers
select
new XElement("id", id),
new XElement("address", address)
);
Customer will contain a new node
<Customer>
<id>ann</id>
<address>canada</address>
</Customer>
doc.Element("customers").Elements(customer).ToList().Remove();
but this is not working. How can I remove the element from the xml?
Tom,
Try this...
private static void RemoveNode(string sID)
{
XDocument doc = XDocument.Load(#"D:\\Projects\\RemoveNode.xml");
var v = from n in doc.Descendants("Customer")
where n.Element("id").Value == sID
select n;
v.Remove();
doc.Save(#"D:\\Projects\\RemoveNode.xml");
}
This removed one node when I called it using
RemoveNode("michle");
Hope this helps.
Your main mistake is that you are creating new nodes that not attached with the source document instead of retrieving existed nodes from it.
You can use article "Removing Elements, Attributes, and Nodes from an XML Tree" on MSDN as a guideline to manipulating XML data.
For example, use XNode.Remove() method to delete one node from the tree or Extensions.Remove<T>(this IEnumerable<T> source) where T : XNode to remove every node in the source collection of nodes:
doc.Descendants("Customer")
.Where(x => x.Element("id").Value == id)
.Remove();
But you also need to save document via Save method after that for commit your changes:
doc.Save();
You can remove this way based on id
xdoc.Descendants("Customer")
.Where(x => (string)x.Element("id") == "michle")
.Remove();
**I have an XML like this-
<?xml version="1.0" encoding="UTF-8"?>
<Tool_Parent>
<tool name="ABCD" id="226">
<category>Centralized</category>
<extension_id>0</extension_id>
<uses_ids>16824943 16824944</uses_ids>
</tool>
<tool name="EFGH" id="228">
<category>Automated</category>
<extension_id>0</extension_id>
<uses_ids>92440 16824</uses_ids>
</tool>
</Tool_Parent>
Based on the id of tool i want to print the uses_ids value,i.e if i search for 228 i should get 92440 16824.
I had tried like-
var toolData = (from toolElement in doc.Descendants("tool")
select new Tool_poco
{
a_Name = tool.Attribute("name").Value,
a_Id = tool.Attribute("id").Value,
e_ExtensionId = tool.Element("extension_id").Value,
e_UsesIds =tool.Element("uses_parm_ids").Value
});
where Tool_poco is a poco class for tool node containing declaration for member variable.
Now I want to get information related to a particular tool id in toolData variable.How to do it?
Note: I have variable like-
searched_Tool_id = Tool_Id_txtBx.Text.ToString();
Please let me know a way through which i can modify my above query for toolData.**
You can modify your query as
Tool_poco toolData = (from el in xelement.Elements("Employee")
where (string)el.Attribute("id") == "226"
select new Tool_poco
{
a_Name = el.Attribute("name").Value,
a_Id = el.Attribute("id").Value,
e_ExtensionId = el.Element("Name").Value,
e_UsesIds = el.Element("uses_ids").Value
}).FirstOrDefault();
You could start by doing something like this once you have an XDocument object loaded and ready:
var xdoc = XDocument.Parse(
#"<?xml version=""1.0"" encoding=""utf-8""?>
<Tool_Parent>
<tool name=""ABCD"" id=""226"">
<category>Centralized</category>
<extension_id>0</extension_id>
<uses_ids>16824943 16824944</uses_ids>
</tool>
<tool name=""EFGH"" id=""228"">
<category>Automated</category>
<extension_id>0</extension_id>
<uses_ids>92440 16824</uses_ids>
</tool>
</Tool_Parent>");
var root = xdoc.Root; // Got to have that root
if (root != null)
{
var id228query = (from toolElement in root.Elements("tool")
where toolElement.HasAttributes
where toolElement.Attribute("id").Value.Equals("228")
let xElement = toolElement.Element("uses_ids")
where xElement != null
select xElement.Value).FirstOrDefault();
Console.WriteLine(id228query);
Console.Read();
}
Output: 92440 16824
**Note: In reference to your example, one possible reason it was not working
for you could be that your xml references an element with name "uses_ids",
however, your query references an element with a similar, but not exact,
spelling with name "uses_parm_ids".**
I have a xml structure like this. Can anyone help with a simple linq function to read this xml structure.The itemEntry node repeats according to data. I tried to read the xml using the method below,but i am getting no records in the list. Is this method here correct way to get the details...
List<CX_ITEMLIST> sList =
(from e in XDocument.Load(param.FileName).Root.Elements("itemEntry")
select new CX_ITEMLIST
{
TITLE = (string)e.Element("title"),
YEAR = (string)e.Element("year"),
ITEMNAME = (string)e.Element("itemname"),
CATRYLIST =
(
from p in e.Elements("categorylist").Elements("categories")
select new CATLIST
{
IDTYPE = (string)p.Element("categoryid"),
IDNUMBER = (string)p.Element("categoryName")
}).ToList()
}).ToList();
<itemslist>
<itemInformation>
<itemdate>01/23/2014</itemdate>
<itemcount>57</itemcount>
</itemInformation>
<itemEntry>
<title>Title1</title>
<year>2013</title>
<itemname>testname</itemname>
<categorylist>
<categories>
<categoryid>Category1</categoryid>
<categoryName>Category2</categoryName>
</categories>
<categories>
<categoryid>Category1</categoryid>
<categoryName>Category2</categoryName>
</categories>
</categorylist>
</itemEntry>
<itemEntry>
<title>Title1</title>
<year>2013</title>
<itemname>testname</itemname>
<categorylist>
<categories>
<categoryid>Category1</categoryid>
<categoryName>Category2</categoryName>
</categories>
<categories>
<categoryid>Category1</categoryid>
<categoryName>Category2</categoryName>
</categories>
</categorylist>
</itemEntry>
</itemslist>
You should try with XDocument.
XDocument xdoc = XDocument.Load("file.xml");
The System.Xml.XLinq namespace contains some awesome objects to make this easy.
var xDoc = XDocument.Parse(xml); // load your xml string, or use XDocument.Load() to load an xml file
var itemEntries = xDoc
.Root // refers to itemEntries node
.Descendants("itemEntry"); // gets all itemEntry nodes in an IEnumerable object
This gets you an IEnumerable<XNode> of all the itemEntry nodes.
From there you can do what you need, save the values to a business object, etc.
The above method works properly, i found the issue, my xml tag was having namespace attribute. i tried to get the namespace and append it with Elements while reading
XNamespace ns = xDocument.Root.Attribute("xmlns").Value;
List<CX_ITEMLIST> sList =
(from e in XDocument.Load(param.FileName).Root.Elements(ns + "itemEntry")
select new CX_ITEMLIST
{
TITLE = (string)e.Element(ns + "title"),
YEAR = (string)e.Element(ns + "year"),
ITEMNAME = (string)e.Element(ns + "itemname"),
CATRYLIST =
(
from p in e.Elements(ns + "categorylist").Elements(ns + "categories")
select new CATLIST
{
IDTYPE = (string)p.Element(ns + "categoryid"),
IDNUMBER = (string)p.Element(ns + "categoryName")
}).ToList()
}).ToList();
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);