Develop Reference

XML XSD validation. When it occurs

I cannot understand when validation of XML occurs on Load or on Validate. Here is following code...
XmlDocument doc = null;
try
{
XmlReaderSettings settings = new XmlReaderSettings( );
settings.Schemas.Add("http://xxx/customs/DealFile/Common/ReleaseGoodsMessage",
ConfigurationManager.AppSettings.Get("Schemas"));
settings.ValidationType = ValidationType.Schema;
using (XmlReader reader = XmlReader.Create(path, settings)) {
doc = new XmlDocument( );
doc.Load(reader);
}
ValidationEventHandler eventHandler = new ValidationEventHandler(ValidationEventHandler);
doc.Validate(eventHandler);
}
catch(XmlSchemaException xmlErr)
{
// Do something
}
I expect a validation to occur on line doc.Validate(eventHandler);
However it always occurs on doc.Load(reader); . I've got an exception if something wrong with XML.
XMLHelpers.LoadXML(#"C:\work\Xml2Db\Xml2Db\Data\Tests\BadData\01.xml")
Exception thrown: 'System.Xml.Schema.XmlSchemaValidationException' in System.Xml.dll
xmlErr.Message
"The 'http://xxx/customs/DealFile/Common/ReleaseGoodsMessage:governmentProcedureType' element is invalid -
The value 'a' is invalid according to its datatype 'Int' - The string 'a' is not a valid Int32 value."
And this is the code from Microsoft's example https://learn.microsoft.com/en-us/dotnet/api/system.xml.xmldocument.validate?view=netcore-3.1
try
{
XmlReaderSettings settings = new XmlReaderSettings();
settings.Schemas.Add("http://www.contoso.com/books", "contosoBooks.xsd");
settings.ValidationType = ValidationType.Schema;
XmlReader reader = XmlReader.Create("contosoBooks.xml", settings);
XmlDocument document = new XmlDocument();
document.Load(reader);
ValidationEventHandler eventHandler = new ValidationEventHandler(ValidationEventHandler);
// the following call to Validate succeeds.
document.Validate(eventHandler);
...
It's actually the same.
But, pay attention on comment // the following call to Validate succeeds. . They also expect to get validation on the line document.Validate(eventHandler);
What's going on.

As your block of code sets up the settings object, it sets a schema and the Validator to use ValidationType.Schema (i.e.: use the schema).
When you setup the XmlReader, using your settings it's setup to validate according to the schema, too - which is causing your schema-based error/exception.
The call to document.Validate(eventHandler); is completely redundant, because it will succeed in all circumstances - because the xml has already been validated. The comment is correct "the following call to Validate succeeds" because the document has already been proved valid.

I suspect that you are failing to distinguish between XML that is well-formed and XML that is valid.
A well-formed XML document satisfies all of the rules of the XML specification. If it does not, you should get a well-formedness error from any XML parser.
If you also choose to
a) supply an XSD that describes you XML document and
b) tell your XML processor to validate against that XSD
then the XML processor will also check that the document satisfies the rules in the XML schema (an XML Schema is composed of one or more XSDs).
If you are still not sure, edit your question and supply the error message(s) that you are seeing. You don't need to include any confidential information - the error template is enough to tell which kind of error it is.

Loading XML file from UNC Path not working propertly

I want to load an XML file located on my server so I can get the value of the XML Element called "CheckInterval" and store it on a string called "NewIntervalSet".
I am loading the following XML file called "ConfigFile.xml".
<?xml version="1.0" encoding="utf-8"?>
<Cart>
<CartConfiguration>
<CheckInterval>0.25</CheckInterval>
</CartConfiguration>
</Cart>
The way that I am loading it is the following:
XElement xelement;
xelement = XElement.Load(Path.Combine("\\\\server\\public\\Engineering","ConfigFile.xml"));
The way that I'm storing the XML element "CheckInterval" into the string "NewIntervalSet" is the following:
string NewIntervalSet;
NewIntervalSet=xelement.Descendants("CartConfiguration")
.Select(x => x.Element("CheckInterval").Value).FirstOrDefault();
When I place a breakpoint where the file is being loaded I can see that the file is loading correctly, so I know the path is right, but when it tries to select the XML element it skips this line of code and it returns a null value, therefore a null string on the "NewIntervalSet" variable. I have no idea why is doing this, when I use the same code but the path is on the local machine it works correct.

Your program may be running into a permissions issue. According to MSDN, XElement creates by calling XmlReader.Create, which in turn has the following to say
A default XmlUrlResolver with no credentials is used to access any
external resources such as a document type definition (DTD), entities,
schemas, and so on. If the external resource is located on a network
resource that requires authentication, specify an XmlResolver with the
necessary credentials using the XmlReaderSettings.XmlResolver
property.
Since your XML document is located on a network path, it's using default/null credentials, causing it to get no read permissions and an empty document. Try opening the file as a stream so you can make a run where it reads out text, and then pipe that stream into a new XElement using this overload. Alternatively, instantiate the XmlResolver yourself so you can set the credentials.

I fix this problem by loading the XML file as an XDocument and not as an XElement. The new way that I'm loading the XML file is the following:
XDocument xDocument;
xDocument= XDocument.Load(Path.Combine("\\\\server\\public\\Engineering","ConfigFile.xml"));

How to Save a Generated XSD File

I have some code (in c#) that creates a bunch of XML sheets on the fly. At the end of my code I am generating XSDs based on those XML sheets. I am making the XSDs successfully, but saving them as files is what I cannot figure out. My code so far is basically taken from the MSDN page on generating XSDs from XML sheets:
Directory.CreateDirectory(directoryName);
string[] directoryFiles = Directory.GetFiles(xmlFilePath);
foreach (string xFile in directoryFiles)
{
XmlReader reader = XmlReader.Create(xFile);
XmlSchemaSet schemaSet = new XmlSchemaSet();
XmlSchemaInference schema = new XmlSchemaInference();
schema.TypeInference = XmlSchemaInference.InferenceOption.Relaxed;
schemaSet = schema.InferSchema(reader);
//insert code here to save the file
//stored in schemaSet.Schemas()
}
Any help is appreciated. Thanks.

XMLSchemaSet has a method called Schemas() that returns a collection of all the schemas in the set. MSDN has a page that describes how to access these.
Simply access each Schema in the set using the code in the link above and write it using the example here.

Validate xml via dtd, different directory for dtd

I am trying to validate an xml file via a .dtd. I have write this validator:
public bool Validation(XmlDocument xmlDoc)
{
var xml = XmldocToString(xmlDoc);
var r = new XmlTextReader(new StringReader(xml));
var settings = new XmlReaderSettings();
var sb = new StringBuilder();
settings.ProhibitDtd = false;
settings.ValidationType = ValidationType.DTD;
settings.ValidationEventHandler += (a, e) =>
{
sb.AppendLine(e.Message);
_isValid = false;
};
XmlReader validator = XmlReader.Create(r, settings);
while (validator.Read())
{
}
validator.Close();
return _isValid;
}
The problem is that I must have the dtd file in bin directory of the Solution. I want to chose a diferent directory to keep the .dtd file and i really can't find how.
Thank you for your time.

Declare in the Xml file the association with the DTD:
Example in case the dtd is stored in a remote server:
<!DOCTYPE Catalog PUBLIC "abc/Catalog" "http://xyz.abc.org/dtds/catalog.dtd">
Take a look at that wiki page and at that site for more options and information about Xml files and DTD association.
Example in case the dtd is placed locally (SYSTEM):
How to reference a DTD from a document:
Assuming the top element of the document is spec and the dtd is placed
in the file mydtd in the subdirectory dtds of the directory from where
the document were loaded:
<!DOCTYPE spec SYSTEM "dtds/mydtd">
Notes:
The system string is actually an URI-Reference (as defined in RFC
2396) so you can use a full URL string indicating the location of your
DTD on the Web. This is a really good thing to do if you want others
to validate your document. It is also possible to associate a PUBLIC
identifier (a magic string) so that the DTD is looked up in catalogs
on the client side without having to locate it on the web. A DTD
contains a set of element and attribute declarations, but they don't
define what the root of the document should be. This is explicitly
told to the parser/validator as the first element of the DOCTYPE
declaration.
(Excerpt from here)

Validate XDocument against a particular schema

I have an XDocument file that I have loaded. (confirmed the working). I need to validate this document. To do so I have an XSD file that I attached to the project as a embedded resource. I load
the xsd with these line of code:
Assembly assembly = Assembly.GetExecutingAssembly();
Stream stream = assembly.GetManifestResourceStream("Project.Models.Ci.def.xsd");
How can I now validate the XML against this XSD? I only need to know if the document is valid or not, so nothing fancy.

There is a Validate extension method that might meet your needs. Take a look at this documentation on MSDN - it has sample code as well:
Extensions.Validate Method (XDocument, XmlSchemaSet, ValidationEventHandler, Boolean)