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How does C# XML validation against XSD work? [duplicate]

I have an XML file with a specified schema location such as this:
xsi:schemaLocation="someurl ..\localSchemaPath.xsd"
I want to validate in C#. Visual Studio, when I open the file, validates it against the schema and lists errors perfectly. Somehow, though, I can't seem to validate it automatically in C# without specifying the schema to validate against like so:
XmlDocument asset = new XmlDocument();
XmlTextReader schemaReader = new XmlTextReader("relativeSchemaPath");
XmlSchema schema = XmlSchema.Read(schemaReader, SchemaValidationHandler);
asset.Schemas.Add(schema);
asset.Load(filename);
asset.Validate(DocumentValidationHandler);
Shouldn't I be able to validate with the schema specified in the XML file automatically ? What am I missing ?

You need to create an XmlReaderSettings instance and pass that to your XmlReader when you create it. Then you can subscribe to the ValidationEventHandler in the settings to receive validation errors. Your code will end up looking like this:
using System.Xml;
using System.Xml.Schema;
using System.IO;
public class ValidXSD
{
public static void Main()
{
// Set the validation settings.
XmlReaderSettings settings = new XmlReaderSettings();
settings.ValidationType = ValidationType.Schema;
settings.ValidationFlags |= XmlSchemaValidationFlags.ProcessInlineSchema;
settings.ValidationFlags |= XmlSchemaValidationFlags.ProcessSchemaLocation;
settings.ValidationFlags |= XmlSchemaValidationFlags.ReportValidationWarnings;
settings.ValidationEventHandler += new ValidationEventHandler(ValidationCallBack);
// Create the XmlReader object.
XmlReader reader = XmlReader.Create("inlineSchema.xml", settings);
// Parse the file.
while (reader.Read()) ;
}
// Display any warnings or errors.
private static void ValidationCallBack(object sender, ValidationEventArgs args)
{
if (args.Severity == XmlSeverityType.Warning)
Console.WriteLine("\tWarning: Matching schema not found. No validation occurred." + args.Message);
else
Console.WriteLine("\tValidation error: " + args.Message);
}
}

A simpler way, if you are using .NET 3.5, is to use XDocument and XmlSchemaSet validation.
XmlSchemaSet schemas = new XmlSchemaSet();
schemas.Add(schemaNamespace, schemaFileName);
XDocument doc = XDocument.Load(filename);
string msg = "";
doc.Validate(schemas, (o, e) => {
msg += e.Message + Environment.NewLine;
});
Console.WriteLine(msg == "" ? "Document is valid" : "Document invalid: " + msg);
See the MSDN documentation for more assistance.

personally I favor validating without a callback:
public bool ValidateSchema(string xmlPath, string xsdPath)
{
XmlDocument xml = new XmlDocument();
xml.Load(xmlPath);
xml.Schemas.Add(null, xsdPath);
try
{
xml.Validate(null);
}
catch (XmlSchemaValidationException)
{
return false;
}
return true;
}
(see Timiz0r's post in Synchronous XML Schema Validation? .NET 3.5)

The following example validates an XML file and generates the appropriate error or warning.
using System;
using System.IO;
using System.Xml;
using System.Xml.Schema;
public class Sample
{
public static void Main()
{
//Load the XmlSchemaSet.
XmlSchemaSet schemaSet = new XmlSchemaSet();
schemaSet.Add("urn:bookstore-schema", "books.xsd");
//Validate the file using the schema stored in the schema set.
//Any elements belonging to the namespace "urn:cd-schema" generate
//a warning because there is no schema matching that namespace.
Validate("store.xml", schemaSet);
Console.ReadLine();
}
private static void Validate(String filename, XmlSchemaSet schemaSet)
{
Console.WriteLine();
Console.WriteLine("\r\nValidating XML file {0}...", filename.ToString());
XmlSchema compiledSchema = null;
foreach (XmlSchema schema in schemaSet.Schemas())
{
compiledSchema = schema;
}
XmlReaderSettings settings = new XmlReaderSettings();
settings.Schemas.Add(compiledSchema);
settings.ValidationEventHandler += new ValidationEventHandler(ValidationCallBack);
settings.ValidationType = ValidationType.Schema;
//Create the schema validating reader.
XmlReader vreader = XmlReader.Create(filename, settings);
while (vreader.Read()) { }
//Close the reader.
vreader.Close();
}
//Display any warnings or errors.
private static void ValidationCallBack(object sender, ValidationEventArgs args)
{
if (args.Severity == XmlSeverityType.Warning)
Console.WriteLine("\tWarning: Matching schema not found. No validation occurred." + args.Message);
else
Console.WriteLine("\tValidation error: " + args.Message);
}
}
The preceding example uses the following input files.
<?xml version='1.0'?>
<bookstore xmlns="urn:bookstore-schema" xmlns:cd="urn:cd-schema">
<book genre="novel">
<title>The Confidence Man</title>
<price>11.99</price>
</book>
<cd:cd>
<title>Americana</title>
<cd:artist>Offspring</cd:artist>
<price>16.95</price>
</cd:cd>
</bookstore>
books.xsd
<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema"
xmlns="urn:bookstore-schema"
elementFormDefault="qualified"
targetNamespace="urn:bookstore-schema">
<xsd:element name="bookstore" type="bookstoreType"/>
<xsd:complexType name="bookstoreType">
<xsd:sequence maxOccurs="unbounded">
<xsd:element name="book" type="bookType"/>
</xsd:sequence>
</xsd:complexType>
<xsd:complexType name="bookType">
<xsd:sequence>
<xsd:element name="title" type="xsd:string"/>
<xsd:element name="author" type="authorName"/>
<xsd:element name="price" type="xsd:decimal"/>
</xsd:sequence>
<xsd:attribute name="genre" type="xsd:string"/>
</xsd:complexType>
<xsd:complexType name="authorName">
<xsd:sequence>
<xsd:element name="first-name" type="xsd:string"/>
<xsd:element name="last-name" type="xsd:string"/>
</xsd:sequence>
</xsd:complexType>
</xsd:schema>

I had do this kind of automatic validation in VB and this is how I did it (converted to C#):
XmlReaderSettings settings = new XmlReaderSettings();
settings.ValidationType = ValidationType.Schema;
settings.ValidationFlags = settings.ValidationFlags |
Schema.XmlSchemaValidationFlags.ProcessSchemaLocation;
XmlReader XMLvalidator = XmlReader.Create(reader, settings);
Then I subscribed to the settings.ValidationEventHandler event while reading the file.

Using xmlwriter to custom write XML

I am trying to use xmlwriter to customize my xml file. I have tried using a class to serialize to xml but it does not seem to work. My goal is to have multiple namespace definitions within the "AddO" element, with each element under the messages having a prefix.
Click event:
XmlWriterSettings objSetting = new XmlWriterSettings();
objSetting.Indent = true;
objSetting.NewLineOnAttributes = true;
System.Text.StringBuilder sb = new System.Text.StringBuilder();
using (XmlWriter objWriter = XmlWriter.Create(sb, objSetting))
{
//Request
objWriter.WriteStartDocument();
objWriter.WriteStartElement("Request");
objWriter.WriteStartElement("SName");
objWriter.WriteValue("AocD");
objWriter.WriteEndElement();
objWriter.WriteStartElement("Message");
//objWriter.WriteStartElement("pd", "AddO", "www.google.com");
objWriter.WriteStartElement("pd", "AddO", "www.google.com");
objWriter.WriteStartElement("aoc","CaseD");
objWriter.WriteStartElement("CaseA");
objWriter.WriteStartElement("DocE");
objWriter.WriteEndElement();
objWriter.WriteEndElement();
objWriter.WriteEndElement();
objWriter.WriteEndElement();//CaseD End
objWriter.WriteEndElement();//Message End
objWriter.WriteEndElement();//Request End
objWriter.WriteEndDocument();
File.WriteAllText(Server.MapPath("~/images/test.xml"), sb.ToString());
I get this XML Result:
<?xml version="1.0" encoding="utf-16"?>
<Request>
<SName>AocD</SName>
<Message>
<iepd:AddO xmlns:iepd="www.google.com">
<aoc xmlns="CaseD">
<CaseA>
<DocE>
</DocE>
</CaseA>
</aoc>
</iepd:AddO>
</Message>
</Request>
Trying to get:
<?xml version="1.0" encoding="utf-16"?>
<Request>
<SName>AocD</SName>
<Message>
<iepd:AddO xmlns:iepd="www.google.com" xmlns:a="www.goo.com" xmlns:b="www.gle.com" xmlns:d="www.le.com">
<a:CaseD">
<b:CaseA>
<d:DocE>
</d:DocE>
</b:CaseA>
</a:CaseD>
</iepd:AddO>
</Message>
</Request>

Not able to validate xml by converting xml string to stream

I getting xml through web service in string format and to pass through xmlreader, I am converting the string to a stream object. But cannot figure out what I am missing. The xml and schema mentioned here is a sample.
class Program
{
static void Main(string[] args)
{
try
{
XmlDocument doc = new XmlDocument();
doc.Load("books.xml");
StringWriter sw = new StringWriter();
XmlTextWriter tx = new XmlTextWriter(sw);
doc.WriteTo(tx);
string leadxml = sw.ToString();
XmlReaderSettings xmlSettings = new XmlReaderSettings();
xmlSettings.Schemas = new System.Xml.Schema.XmlSchemaSet();
xmlSettings.Schemas.Add(string.Empty,"books.xsd");
xmlSettings.ValidationType = ValidationType.Schema;
byte[] byteArray = Encoding.ASCII.GetBytes(leadxml);
MemoryStream stream = new MemoryStream(byteArray);
XmlReader reader = XmlReader.Create(stream, xmlSettings);
// Parse the file.
while (reader.Read());
}
catch (Exception ex)
{
Console.WriteLine(ex.Message);
}
}
}
xml is:
<?xml version="1.0" encoding="utf-8" ?>
<bookstore>
<book genre="autobiography" publicationdate="1981-03-22" ISBN="1-861003-11-0"/>
</bookstore>
xsd is:
<?xml version="1.0" encoding="utf-8"?>
<xs:schema attributeFormDefault="unqualified" elementFormDefault="qualified" xmlns:xs="http://www.w3.org/2001/XMLSchema">
<xs:element name="bookstore">
<xs:complexType>
<xs:sequence>
<xs:element maxOccurs="unbounded" name="book">
</xs:element>
</xs:sequence>
</xs:complexType>
</xs:element>
</xs:schema>

First of all, if all your doing is getting the Xml into a string, this entire block of code is unnecessary:
XmlDocument doc = new XmlDocument();
doc.Load("books.xml");
StringWriter sw = new StringWriter();
XmlTextWriter tx = new XmlTextWriter(sw);
doc.WriteTo(tx);
string leadxml = sw.ToString();
Instead just do:
string leadxml = File.ReadAllText("books.xml");
Secondly, if you have a string already, it is completely unnecessary to do all this conversion on the string. The XmlReader.Create method has a signature which accepts a TextReader. StringReader derives from TextReader. Therefore, this:
byte[] byteArray = Encoding.ASCII.GetBytes(leadxml);
MemoryStream stream = new MemoryStream(byteArray);
XmlReader reader = XmlReader.Create(stream, xmlSettings);
Can be replaced with this:
StringReader leadxmlStringReader = new StringReader(leadXml);
XmlReader reader = XmlReader.Create(leadxmlStringReader, xmlSettings);
For any further assistance with this question, you will need to provide Exception details and/or specific error messages.

StringWriter assumes a UTF-16 encoding by default, which means you'll get an XML declaration with UTF-16 in it. You're then using Encoding.ASCII to get a binary representation though, which is incompatible with the UTF-16 declaration.
To be honest, it's not really clear why you're doing this in the first place - there's almost certainly a better way of achieving your goal, but we can't really tell what your goal is, so we can't advise what that better way might be.
EDIT: For example, this might be what you're really after:
XmlReaderSettings xmlSettings = new XmlReaderSettings
{
Schemas = { { "", "books.xsd" } },
ValidationType = ValidationType.Schema
}
using (var reader = XmlReader.Create("books.xml", xmlSettings))
{
while (reader.Read()) {}
}

Getting InvalidOperationException when Deserializing in C#

I'm using an XML based .config file for storing some records.
my XML is below:
<?xml version="1.0" encoding="utf-8"?>
<Data_List xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
<Configuration>
<Name>1st Week</Name>
<Binary>
<Field>field1</Field>
<Version>1.0</Version>
</Binary>
<Binary>
<Field>field2</Field>
<Version>2.0</Version>
</Binary>
</Configuration>
<Configuration>
<Name>2nd Week</Name>
<Binary>
<Field>field1</Field>
<Version>2.0</Version>
</Binary>
<Binary>
<Field>field2</Field>
<Version>4.0</Version>
</Binary>
</Configuration>
</Data_List>
I'm using C# code as follows:
public Binary
{
public String Field;
public String Version;
}
public Configuration
{
public String Name;
public List<Binary> Binary_List = new List<Binary>();
public GetfromXML()
{
List<Configuration> lists = new List<Configuration>();
TextReader reader = new StreamReader("Data_List.config");
XmlSerializer serializer = new XmlSerializer(typeof(List<Configuration>));
lists=(List<Configuration>)serializer.Deserialize(reader);
reader.Close();
}
I'm getting an exception saying "There's an error in XML document(2,2)".
Can anyone pls help?

I think the problem is that your model is not well structurized. In other words, serializer does not know how to read your .xml.
Your xml is wrong. When you have List< T > there would be an:
<ArrayOfT></ArrayOfT>
in .XML. Here is how you need to do it!
First, try using xml attributes from System.Xml.Serialization(i.e. [XmlArray()])
It would be better that you use FileStream instead of just pointing out URI
using(var filestream = new FileStream(//your uri, FIleMode.Open)
{
}
Use properties instead of variables. Because later on you may want to bind.
Example of my code how i managed to solve that issue:
public ServiceMap Deserialize()
{
ServiceMap serviceMap = new ServiceMap();
try
{
using (var fileStream = new FileStream(Settings.ServiceMapPath, FileMode.Open))
{
XmlReaderSettings settings = new XmlReaderSettings();
settings.IgnoreComments = true;
using (XmlReader reader = XmlReader.Create(fileStream, settings))
{
serviceMap = _serializer.Deserialize(reader) as ServiceMap;
}
}
}
catch (FileNotFoundException)
{
MessageBox.Show("File 'ServiceMap.xml' could not be found!");
}
return serviceMap;
}
My ServiceMap class:
[XmlRoot("ServiceMap")]
public class ServiceMap
{
[XmlArray("Nodes")]
[XmlArrayItem("Node")]
public List<Node> Nodes = new List<Node>();
[XmlArray("Groups")]
[XmlArrayItem("Group")]
public List<Group> Groups = new List<Group>();
[XmlArray("Categories")]
[XmlArrayItem("Category")]
public List<Category> Categories = new List<Category>();
}
EDIT: My XML:
<?xml version="1.0" encoding="utf-8"?>
<ServiceMap xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http:// www.w3.org/2001/XMLSchema">
<Nodes>
<Node Name="Predrag">
<Children>
<Child>dijete1</Child>
<Child>dijete2</Child>
<Child>dijete3</Child>
<Child>dijete4</Child>
</Children>
<Parents>
<Parent>roditelj1</Parent>
<Parent>roditelj2</Parent>
<Parent>roditelj3</Parent>
</Parents>
<Group Name="Grupa" />
<Category Name="Kategorija" />
</Node>
<Node Name="Tami">
<Children>
<Child>dijete1</Child>
<Child>dijete2</Child>
</Children>
<Parents>
<Parent>roditelj1</Parent>
</Parents>
<Group Name="Grupa2" />
<Category Name="Kategorija2" />
</Node>

How best to test the validity of XML from a method?

I have some WCF methods that are used to transmit information from a server application to a website frontend for use in binding. I'm sending the result as an XElement that is a root of an XML tree containing the data I want to bind against.
I'd like to create some tests that examine the data and ensure it comes across as expected.
My current thinking is this: Every method that returns an XElement tree has a corresponding schema (.XSD) file. This file is included within the assembly that contains my WCF classes as an embedded resource.
Tests call the method on these methods and compares the result against these embedded schemas.
Is this a good idea? If not, what other ways can I use to provide a "guarantee" of what kind of XML a method will return?
If it is, how do you validate an XElement against a schema? And how can I get that schema from the assembly it's embedded in?

Id say validating xml with a xsd schema is a good idea.
How to validate a XElement with the loaded schema:
As you see in this example you need to validate the XDocument first to get populate the "post-schema-validation infoset" (There might be a solution to do this without using the Validate method on the XDOcument but Im yet to find one):
String xsd =
#"<xsd:schema xmlns:xsd='http://www.w3.org/2001/XMLSchema'>
<xsd:element name='root'>
<xsd:complexType>
<xsd:sequence>
<xsd:element name='child1' minOccurs='1' maxOccurs='1'>
<xsd:complexType>
<xsd:sequence>
<xsd:element name='grandchild1' minOccurs='1' maxOccurs='1'/>
<xsd:element name='grandchild2' minOccurs='1' maxOccurs='2'/>
</xsd:sequence>
</xsd:complexType>
</xsd:element>
</xsd:sequence>
</xsd:complexType>
</xsd:element>
</xsd:schema>";
String xml = #"<?xml version='1.0'?>
<root>
<child1>
<grandchild1>alpha</grandchild1>
<grandchild2>beta</grandchild2>
</child1>
</root>";
XmlSchemaSet schemas = new XmlSchemaSet();
schemas.Add("", XmlReader.Create(new StringReader(xsd)));
XDocument doc = XDocument.Load(XmlReader.Create(new StringReader(xml)));
Boolean errors = false;
doc.Validate(schemas, (sender, e) =>
{
Console.WriteLine(e.Message);
errors = true;
}, true);
errors = false;
XElement child = doc.Element("root").Element("child1");
child.Validate(child.GetSchemaInfo().SchemaElement, schemas, (sender, e) =>
{
Console.WriteLine(e.Message);
errors = true;
});
How to read the embedded schema from an assembly and add it to the XmlSchemaSet:
Assembly assembly = Assembly.GetExecutingAssembly();
// you can use reflector to get the full namespace of your embedded resource here
Stream stream = assembly.GetManifestResourceStream("AssemblyRootNamespace.Resources.XMLSchema.xsd");
XmlSchemaSet schemas = new XmlSchemaSet();
schemas.Add(null, XmlReader.Create(stream));

If you're doing some light-weight work and XSDs are overkill, consider also possibly strongly typing your XML data. For example, I have a number of classes in a project that derive from XElement. One is ExceptionXElement, another is HttpHeaderXElement, etc. In them, I inherit from XElement and add Parse and TryParse methods that take strings containing XML data to create an instance from. If TryParse() returns false, the string does not conform to the XML data I expect (the root element has the wrong name, missing children elements, etc.).
For example:
public class MyXElement : XElement
{
public MyXElement(XElement element)
: base(element)
{ }
public static bool TryParse(string xml, out MyXElement myElement)
{
XElement xmlAsXElement;
try
{
xmlAsXElement = XElement.Parse(xml);
}
catch (XmlException)
{
myElement = null;
return false;
}
// Use LINQ to check if xmlAsElement has correct nodes...
}