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);
Related
<?xml version="1.0" encoding="utf-8"?>
<serv:message
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:serv="http://www.webex.com/schemas/2002/06/service" xsi:schemaLocation="http://www.webex.com/schemas/2002/06/service http://www.webex.com/schemas/2002/06/service.xsd">
<header>
<securityContext>
<webExID/>
<password/>
<siteID/>
<partnerID/>
</securityContext>
</header>
<body>
<bodyContent xsi:type="java:com.webex.service.binding.training.CreateTrainingSession"
xmlns="http://www.webex.com/schemas/2002/06/service/training"
xmlns:com="http://www.webex.com/schemas/2002/06/common"
xmlns:sess="http://www.webex.com/schemas/2002/06/session"
xmlns:serv="http://www.webex.com/schemas/2002/06/service"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.webex.com/schemas/2002/06/service/training http://www.webex.com/schemas/2002/06/service/training/trainingsession.xsd">
<sess:accessControl>
<sess:sessionPassword/>
</sess:accessControl>
<sess:schedule></sess:schedule>
<metaData>
<sess:confName/>
<agenda/>
<description/>
<greeting/>
<location/>
</metaData>
<enableOptions>
<chat/>
<poll/>
<audioVideo/>
<fileShare/>
<applicationShare/>
<desktopShare/>
<annotation/>
<fullScreen/>
<voip/>
</enableOptions>
</bodyContent>
</body>
</serv:message>
Above XML is standard VILT Create Event xml and I need to populate it with proper data.
The issue is I am able to get "securityContent" element using below code and node holds total count of child elements that is 4:
var node = xmlDoc.SelectNodes("/serv:message/header/securityContext/*", GetNameSpace(xmlDoc.NameTable));
But when I try to get another node i.e. "metaData" then I get Count 0 and way to getting element is exactly same except the path to the element.
Below is sample code that I've tried but not working:
static void Main(string[] args)
{
var xmlPathh = #"C:\Users\SKMEENA\Desktop\VILT.xml";// this holds above xml
XmlDocument xmlDoc = new XmlDocument();
xmlDoc.Load(xmlPathh);
var node = xmlDoc.SelectNodes("/serv:message/header/securityContext/*", GetNameSpace(xmlDoc.NameTable));
var member = xmlDoc.SelectNodes("/serv:message/body/bodyContent/metaData/*", GetNameSpace(xmlDoc.NameTable));
}
static XmlNamespaceManager GetNameSpace(XmlNameTable objNameTable)
{
XmlNamespaceManager objNsManager =new XmlNamespaceManager(objNameTable);
objNsManager.AddNamespace("serv", "http://www.webex.com/schemas/2002/06/service");
objNsManager.AddNamespace("ns1", "http://www.webex.com/schemas/2002/06/service/site");
return objNsManager;
}
Anybody has any idea what is wrong with above code and how can I make it working?
The bodyContent node has a default namespace which applies to it and all its children.
You need to add it to the NamespaceManager and then use it in the XPath
var member = xmlDoc.SelectSingleNode("/serv:message/body/body:bodyContent/body:metaData", GetNameSpace(xmlDoc.NameTable));
member.OuterXml.Dump();
static XmlNamespaceManager GetNameSpace(XmlNameTable objNameTable)
{
XmlNamespaceManager objNsManager =new XmlNamespaceManager(objNameTable);
objNsManager.AddNamespace("serv", "http://www.webex.com/schemas/2002/06/service");
objNsManager.AddNamespace("ns1", "http://www.webex.com/schemas/2002/06/service/site");
objNsManager.AddNamespace("body", "http://www.webex.com/schemas/2002/06/service/training");
objNsManager.AddNamespace("sess","http://www.webex.com/schemas/2002/06/session");
return objNsManager;
}
dotnetfiddle
I am working with an XML api, which returns the following:
<inventory>
<product inventoryId="1722474" externalReference="SM" site="global" total="0" allocated="0" available="0" frozen="0" onOrder="0" lastStockChangeId="505401" lastLineRequirementChangeId="0"/>
<product inventoryId="1722476" externalReference="PM" site="global" total="0" allocated="0" available="0" frozen="0" onOrder="0" lastStockChangeId="243256" lastLineRequirementChangeId="0"/>
.... 1000s of nodes ....
</inventory>
So, from this returned xml nodes, I am only interested in the following fields/attributes externalReference and available.
Therefore; I created the following class to describe the xml content I am going to deserialize/parse:
[XmlRoot(ElementName = "product")]
public class StockLevelProduct
{
[XmlAttribute(AttributeName = "externalReference")]
public string ExternalReference { get; set; }
[XmlAttribute(AttributeName = "available")]
public string Available { get; set; }
}
[XmlRoot(ElementName = "inventory")]
public class StockLevelResult
{
[XmlElement(ElementName = "product")]
public List<StockLevelProduct> Product { get; set; }
}
Then I put it all together like this:
// Init
StockLevelResult stockLevelResult;
// Anticipate errors
try
{
// Generate request url
string requestUrl = string.Format("{0}/remotewarehouse/inventory.xml?channel={1}",
apiUrl,
apiChannel);
// Call api
string apiResultXmlString = ApiGet(requestUrl);
// Fix api result xml string
if (!apiResultXmlString.Contains("<?xml"))
apiResultXmlString = "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\r\n" + apiResultXmlString;
// Deserialize xml string to object
stockLevelResult = XmlParser.Parse<StockLevelResult>(apiResultXmlString);
}
catch (Exception ex)
{
Console.WriteLine("Failed to download stock levels - " + ex.Message);
}
Note* the returned xml string from the API server does not contain <?xml version="1.0" encoding="UTF-8"?> so I manually add it. Note sure if XmlParser.Parse requires it.
When this code executes; I get the following exception being thrown:
There is an error in XML document (1871, 60)
Any ideas why this isn't working? Is it an issue with the returned XML string? or the way I am trying to parse/deserialize it?
Try this
XmlSerializer xs = new XmlSerializer(typeof(StockLevelResult));
StringReader sReader = new StringReader(apiResultXmlString);
XmlTextReader reader = new XmlTextReader(sReader);
stockLevelResult = (StockLevelResult)xs.Deserialize(reader);
The exception was caused by bad data in the api XML response:
<product inventoryId="1726460" externalReference="V02002B&R"
site="global" total="0" allocated="0" available="0" frozen="0"
onOrder="0" lastStockChangeId="76231"
lastLineRequirementChangeId="0"/>
i.e. & in this attribute externalReference="V02002B&R"
I fixed it thanks to this answer like this:
// Call api
string apiResultXmlString = ApiGet(requestUrl);
// Fix api result xml string
if (!apiResultXmlString.Contains("<?xml"))
apiResultXmlString = "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\r\n" + apiResultXmlString;
// Fix bad response data
string pattern = "(?<start>>)(?<content>.+?(?<!>))(?<end><)|(?<start>\")(?<content>.+?)(?<end>\")";
apiResultXmlString = System.Text.RegularExpressions.Regex.Replace(apiResultXmlString, pattern, m =>
m.Groups["start"].Value +
System.Web.HttpUtility.HtmlEncode(System.Web.HttpUtility.HtmlDecode(m.Groups["content"].Value)) +
m.Groups["end"].Value);
I have already an XML file whose structure is like this:
<?xml version="1.0" encoding="utf-16"?>
<configuration>
<FilePath>C:\Recordings</FilePath>
<Timer>2</Timer>
</configuration>
I want to to add one more child in <configuration> and want the new structure like shown below. Moreover, before adding I also want to make sure that the new child added is present or not.
<?xml version="1.0" encoding="utf-16"?>
<configuration>
<FilePath>C:\Recordings</FilePath>
<Timer>2</Timer>
<LastSyncTime>Some Value</LastSyncTime>
</configuration>
If <LastSyncTime> is not there, then and only it should be added otherwise not.
I have tried so far as given below:
try
{
XmlDocument doc = new XmlDocument();
doc.Load(newpath);
XmlNodeList nodes = doc.SelectNodes("LastSyncDateTime");
if(nodes.Count == 0) //Means LastSyncDateTime node does not exist
{
XmlNode mynode = doc.CreateNode(XmlNodeType.Text, "LastSyncDateTime",null);
mynode.Value = DateTime.Now.ToString() + "";
doc.AppendChild(mynode);
}
foreach (XmlNode node in nodes)
{
if (node.LastChild != null)
{
LastSyncDateTime = (node.LastChild.InnerText);
Console.WriteLine("Last Date Time is : " + LastSyncDateTime);
}
}
}
catch (Exception ex)
{
//throw ex;
string str = (String.Format("{0} {1}", ex.Message, ex.StackTrace));
Console.WriteLine(str);
}
But I am getting exception. Please suggest me best working solution for this.
Thanks
EDIT : I am getting the following exception:
[System.InvalidOperationException] = {"The specified node cannot be inserted as the valid child of this node, because the specified node is the wrong type."}
You should've used XmlNodeType.Element instead of XmlNodeType.Text. And it needs some other fixes as shown below :
.....
XmlNodeList nodes = doc.SelectNodes("//LastSyncDateTime");
if (nodes.Count == 0) //Means LastSyncDateTime node does not exist
{
XmlNode mynode = doc.CreateNode(XmlNodeType.Element, "LastSyncDateTime", null);
//set InnerText instead of Value
mynode.InnerText = DateTime.Now.ToString();
//append to root node (DocumentElement)
doc.DocumentElement.AppendChild(mynode);
}
.....
Thank you very much for reading my question.
the bottom is the sample of my xml file.please refer that.
i did some xml files before, but by "CMarkXml". "IntoElement, OutofElement", is very clear.
but when C#...i was lost..
1: how to read & write my xml file without using the tag name. i see some articles about operation on xml file by c#, but all assumed that known the tag name.
2: if without tag name, it is very difficult or not recommend. then how to read & write my xml file by XmlDocument? (sorry, but no Ling please, i am very faint with that...).
3: my idear is, for the xml file, get out some section, we still could parse the section by xmldocument.
4: for the write/modify the xml file, of course, should contain delete some section, delete some "leaf", change the attributes...
Thank you very much for reading the long question, and any help i will very appreciate. If you have a good sample code but not continent paste them here, could you send it to "erlvde#gmail.com"?
<root>
<a>i belong to a</a>
<b>
<bb>
<bb>1</bb>
<bb>2</bb>
<bb>3</bb>
<bb>4</bb>
<bb>5</bb>
</bb>
<bb>
<bb>1</bb>
<bb>2</bb>
<bb>3</bb>
<bb>4</bb>
<bb>5</bb>
<bb>
....(other <bb>)
</b>
</root>
Read your xml into XmlDocument:
var xmlDocument = new XmlDocument();
xmlDocument.LoadXml("XML HERE");
Access child nodes:
xmlDocument.ChildNodes[1]
But it's also true that it's very error prone
You can also check if you have child nodes at all:
xmlDocument.HasChildNodes
And get number of child nodes:
xmlDocument.ChildNodes.Count
It looks to me like your elements names contain identifiers. If that is the case, and you have control over the XML schema, I would highly recommend changing your XML to contain elements and/or attributes indicating your identifiers and then use the built in XmlSerializer class for serializing to and from XML. It has many modifiers available, such as XmlElement and XmlAttribute among many others, for formatting the output.
Here is a tutorial to get you started.
If possible, change your XML to something like following which would make it far simpler to manipulate...again if changing the schema is a possibility.
<root>
<a>i belong to a</a>
<b>
<bb id="1">
<bb>1</bb>
<bb>2</bb>
<bb>3</bb>
<bb>4</bb>
<bb>5</bb>
</bb>
<bb id="2">
<bb>1</bb>
<bb>2</bb>
<bb>3</bb>
<bb>4</bb>
<bb>5</bb>
<bb>
</b>
</root>
Edit this edit reflects the changes you made to your XML
Here is a simple console application which will serialize an object to an XML file and then rehydrate it.
Expected XML
<?xml version="1.0" encoding="utf-8"?>
<root xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
<a>i belong to a</a>
<b>
<bb>
<bb>1</bb>
<bb>2</bb>
<bb>3</bb>
<bb>4</bb>
<bb>5</bb>
</bb>
<bb>
<bb>1</bb>
<bb>2</bb>
<bb>3</bb>
<bb>4</bb>
<bb>5</bb>
</bb>
</b>
</root>
Simple Console Application Demonstration
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Xml.Serialization;
using System.IO;
namespace ConsoleApplication1
{
class Program
{
static void Main(string[] args)
{
var items = new root
{
a = "i belong to a",
b = new List<bb>
{
new bb
{
bbClassProperty = new List<int>
{
1,
2,
3,
4,
5
}
},
new bb
{
bbClassProperty= new List<int>
{
1,
2,
3,
4,
5
}
}
}
};
XmlSerializer serializer = new XmlSerializer(typeof(root));
using (var textWriter = new StreamWriter(#"C:\root.xml"))
{
serializer.Serialize(textWriter, items);
textWriter.Close();
}
using (var stream = new StreamReader(#"C:\root.xml"))
{
var yourObject = serializer.Deserialize(stream);
}
Console.Read();
}
}
#region [Classes]
public class root
{
public string a { get; set; }
public List<bb> b { get; set; }
}
public class bb
{
[XmlElement("bb")]
public List<int> bbClassProperty { get; set; }
}
#endregion
}
Look into the ChildNodes (and similar) properties and methods on your XmlElement object. These will let you iterate over the children of a node and you can then ask that node for its name.
If you have a XmlNode object, you can use XMLNode.FirstChild to get the child, if it has any. You can also use XMLNode.NextSibling to get the next Node of the same parent node.
Why can't you use the names of the nodes? It's the easiest and most common way. Especially if you use XPath or similar.
XPath is also the answer to your second question.
U can use the class XML reader, a simple example is given here.
using System;
using System.Xml;
class Program
{
static void Main()
{
// Create an XML reader for this file.
using (XmlReader reader = XmlReader.Create("perls.xml"))
{
while (reader.Read())
{
// Only detect start elements.
if (reader.IsStartElement())
{
// Get element name and switch on it.
switch (reader.Name)
{
case "perls":
// Detect this element.
Console.WriteLine("Start <perls> element.");
break;
case "article":
// Detect this article element.
Console.WriteLine("Start <article> element.");
// Search for the attribute name on this current node.
string attribute = reader["name"];
if (attribute != null)
{
Console.WriteLine(" Has attribute name: " + attribute);
}
// Next read will contain text.
if (reader.Read())
{
Console.WriteLine(" Text node: " + reader.Value.Trim());
}
break;
}
}
}
}
}
}
The input file text is:
<?xml version="1.0" encoding="utf-8" ?>
<perls>
<article name="backgroundworker">
Example text.
</article>
<article name="threadpool">
More text.
</article>
<article></article>
<article>Final text.</article>
</perls>
Output
Start element.
Start element.
Has attribute name: backgroundworker
Text node: Example text.
Start element.
Has attribute name: threadpool
Text node: More text.
Start element.
Text node:
Start element.
Text node: Final text.enter code here
You can use the following code to if the file does not contain the headers, in the example above.
XmlReaderSettings settings = new XmlReaderSettings();
settings.ConformanceLevel = ConformanceLevel.Fragment;
reader = XmlReader.Create(filePath, settings)
Would something like this help?
void Iterate(XmlNode parent) {
//do something with
//parent.Name
//parent.Value
//parent.Attributes
foreach(XmlNode child in parent.ChildNodes) {
Iterate(child);
}
}
XmlDocument document = new XmlDocument();
document.Load(filename);
XmlNode parent = document.DocumentElement;
Iterate(parent);
You could also store it like that (sorry for any syntactical error, didn't run it)
public class Document {
public Element DocumentElement { set; get; }
private void Load(string fileName) {
XmlDocument document = new XmlDocument();
document.Load(fileName);
DocumentElement = new Element(this, null);
DocumentElement.Load(document.DocumentElement);
}
}
public class Element {
public string Name { set; get; }
public string Value { set; get; }
//other attributes
private Document document = null;
private Element parent = null;
public Element Parent { get { return parent; } }
public List<Element> Children { set; get; }
private int order = 0;
public Element(Document document, Element parent) {
Name = "";
Value = "";
Children = new List<LayoutElement>();
this.document = document;
this.parent = parent;
order = parent != null ? parent.Children.Count + 1 : 1;
}
private Element GetSibling(bool left) {
if(parent == null) return null;
int add = left ? -1 : +1;
Element sibling = parent.Children.Find(child => child.order == order + add);
return sibling;
}
public Element GetLeftSibling() {
return GetSibling(true);
}
public Element GetRightSibling() {
return GetSibling(false);
}
public void Load(XmlNode node) {
Name = node.Name;
Value = node.Value;
//other attributes
foreach(XmlNode nodeChild in node.Children) {
Element child = new Element(document, this);
child.Load(nodeChild);
Children.Add(child);
}
}
}
Document document = new Document();
document.Load(fileName);
For changing/deleting right now you could iterate the tree and find elements by name, but since name is not unique, you would affect many elements at once. You could add an unique id in every tag like
<bb id="bb1"/>
Then read it in Load function like
id = ((XmlElement)node).GetAttribute("id");
and use this id to iterate through the tree. Sorry I don't have time right now to provide something more detailed.
i have tried several methods of trying to extract values from an XML file but none of them seem to work. I am using C#. The XML Is as follows
<?xml version="1.0" encoding="utf-8"?>
<HostedService xmlns="http://schemas.microsoft.com/windowsazure">
<Url>hosted-service-url</Url>
<ServiceName>hosted-service-name</ServiceName>
<HostedServiceProperties>
<Description>description</Description>
<Location>location</Location>
<AffinityGroup>affinity-group</AffinityGroup>
<Label>label</Label>
</HostedServiceProperties>
</HostedService>
I would like to retrieve
hosted-service-url,
hosted-service-name,
description,
location,
affinity-group and
label
What would be the best of way of retrieving these values?
Edit :
Thanks L.B that method works perfectly. However i have just been told i will have to use the larger XML that is below.
<?xml version="1.0" encoding="utf-8"?>
<HostedService xmlns="http://schemas.microsoft.com/windowsazure">
<Url>hosted-service-url</Url>
<ServiceName>hosted-service-name</ServiceName>
<HostedServiceProperties>
<Description>description</Description>
<Location>location</Location>
<AffinityGroup>affinity-group</AffinityGroup>
<Label>base-64-encoded-name-of-the-service</Label>
</HostedServiceProperties>
<Deployments>
<Deployment>
<Name>deployment-name</Name>
<DeploymentSlot>deployment-slot</DeploymentSlot>
<PrivateID>deployment-id</PrivateID>
<Status>deployment-status</Status>
<Label>base64-encoded-deployment-label</Label>
<Url>deployment-url</Url>
<Configuration>base-64-encoded-configuration-file</Configuration>
<RoleInstanceList>
<RoleInstance>
<RoleName>role-name</RoleName>
<InstanceName>role-instance-name</InstanceName>
<InstanceStatus>instance-status</InstanceStatus>
</RoleInstance>
</RoleInstanceList>
<UpgradeDomainCount>upgrade-domain-count</UpgradeDomainCount>
<RoleList>
<Role>
<RoleName>role-name</RoleName>
<OsVersion>operating-system-version</OsVersion>
</Role>
</RoleList>
<SdkVersion>sdk-version-used-to-create-package</SdkVersion>
<InputEndpointList>
<InputEndpoint>
<RoleName>role-name</RoleName>
<Vip>virtual-ip-address</Vip>
<Port>port-number</Port>
</InputEndpoint>
…
</InputEndpointList>
<Locked>deployment-write-allowed-status</Locked>
<RollbackAllowed>rollback-operation-allowed</RollbackAllowed>
</Deployment>
</Deployments>
</HostedService>
My final question is, there is several repeated tags, such as ,
how can i differentiate between them?
you can use Xml to Linq to parse your xml string. For ex,
var xElem = XElement.Load(new StringReader(xml));
var ns = XNamespace.Get("http://schemas.microsoft.com/windowsazure");
var obj = new
{
ServiceName = xElem.Descendants(ns + "ServiceName").First().Value,
Description = xElem.Descendants(ns + "Description").First().Value,
};
or you can use XmlSerializer
XmlSerializer xs = new XmlSerializer(typeof(HostedService), "http://schemas.microsoft.com/windowsazure");
var obj2 = (HostedService)xs.Deserialize(new StringReader(xml));
public class HostedService
{
public string Url;
public string ServiceName;
public HostedServiceProperties HostedServiceProperties;
}
public class HostedServiceProperties
{
public string Description;
public string Location;
public string AffinityGroup;
public string Label;
}
Maybe you can try samples from XmlDocument ( http://msdn.microsoft.com/en-us/library/d271ytdx.aspx) and and LINQ to XML -( http://msdn.microsoft.com/en-us/library/bb669152.aspx) first and than apply it to your case.