Validating an XML against referenced XSD in C#

Question

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 ?

Refer the MSDN sample : msdn.microsoft.com/en-us/library/… — user1153993
– user1153993, Commented Jan 17, 2012 at 13:19

Kiquenet · Accepted Answer · 2017-03-08 07:35:43Z

182

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);

    }
}

edited Mar 8, 2017 at 7:35

Kiquenet

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answered Apr 15, 2009 at 17:16

Chris McMillan

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8 Comments

IAbstract Over a year ago

+1 although should update to use using clause for completeness :)

Jeff Fol Over a year ago

If you're looking to compare against an XSD file add the following line to the above code: settings.Schemas.Add("YourDomainHere", "yourXSDFile.xsd");

user610064 Over a year ago

To get Line# and position# of the error simply use: args.Exception.LineNumber... in ValidationCallBack

tree Over a year ago

What if the schema i have doesn't have a namespace?

Kiquenet Over a year ago

Using lambda, better IMHO, more clarity code

settings.ValidationEventHandler += (o, args) =>             {                 errors = true;                  // More code             };

|

saluce · Accepted Answer · 2013-10-22 21:54:51Z

127

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.

edited Oct 22, 2013 at 21:54

answered Aug 3, 2012 at 18:47

saluce

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5 Comments

user692942 Over a year ago

That method requires you know the schema beforehand rather than taking the inline schema from the xml.

Anil Purswani Over a year ago

this works fine but throws error when xml document contains some html tag like <catalog>my new catalog....</catalog> in above case html tags like "" creates an issue as it is the value of "<catalog>" ... how to validate it

p0lar_bear Over a year ago

@AnilPurswani: If you wish to put HTML into an XML document, you need to wrap it in CDATA. <catalog><![CDATA[my new catalog....]]></catalog> is the correct way to do that.

Adail Retamal Over a year ago

Simple and elegant! This works very well when validating against a fixed schema set (which is our case, and a big one with multiple folders and files). I'm already thinking about caching the XmlSchemaSet to be reused between calls to the Validator. Thanks a lot!

Sylwester Santorowski Over a year ago

It does not work when the default namespace in XSD is different than in XML.

Community · Accepted Answer · 2017-05-23 12:03:06Z

27

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)

edited May 23, 2017 at 12:03

CommunityBot

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answered Nov 6, 2015 at 10:24

FrankyHollywood

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2 Comments

FrankyHollywood Over a year ago

The callback provides you with some extra information about which line in your xml is not correct. This method is very binary, either right or wrong :)

Leandro Hernández Mira Over a year ago

you can get the exception message :)

matt · Accepted Answer · 2015-07-30 21:28:22Z

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>

saluce · Accepted Answer · 2013-04-17 16:19:07Z

13

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.

edited Apr 17, 2013 at 16:19

saluce

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answered Apr 15, 2009 at 12:54

Welbog

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