Using XML Schema’s in Visual Studio

Well, the only thing inherently wrong with what he was doing was that his schemaLocation attribute does not specify the target namespace. And, he left out the closing schema tag, which I assume was a copy-and-paste typo.  But as far as getting Visual Studio to validate...for some reason it doesn't like the example even though XML Spy validates it.  I would say the Visual Studio IDE is kind of clunky for this anyway.  

In any case, it's better to validate in code, rather than depending on the parser to do it automatically.  For example, just because you've attached a schema to an XML document, there's no guarantee the parser will validate it when it loads.  And, since your schema isn't public, you'd have to use some sort of programmatic method anyway.

In C#, this is how I did it recently for an InfoPath web service.  This is for a relatively complex schema, that actually consists of four component schemas; one to validate a SOAP message, which imports another to validate the web method, which imports a third that validates the payload of the SOAP message.  The third schema includes a fourth that is used as an enumeration for one of the elements in the payload (so I can edit a single simple schema and add new InfoPath forms to my web service).


// Reader for the input stream. Could be from any XML stream
XmlTextReader reader = new XmlTextReader(SoapStreams.InputMessage);

// Need to validate the SOAP message and it's payload
XmlValidatingReader validator = new XmlValidatingReader(reader);

// The schemas make use of import and include, so an XmlUrlResolver is needed
XmlUrlResolver ur = new XmlUrlResolver();

// Impersonates the user, but all auth users will have access
ur.Credentials = CredentialCache.DefaultCredentials;
validator.XmlResolver = ur;

// Tells the validator we want to validate using a schema not a DTD
validator.ValidationType = ValidationType.Schema;

// Now create and add the schema
XmlSchema schema = new XmlSchema();
schema = XmlSchema.Read(new XmlTextReader(HttpContext.Current.Server.MapPath("schemas/InfoPathSchemas/SoapSchema.xsd")), new ValidationEventHandler(ValidationCallBack));
validator.Schemas.Add(schema, ur);

// Delegate to handle validation errors.
validator.ValidationEventHandler += new ValidationEventHandler (ValidationCallBack);

// Finally load the validating reader into a DomDocument.  Validation checks occur at this point.
xmlDoc.Load(validator);


The validation callback function simply throws an exception if validation fails, but you can do other things instead.

            private void ValidationCallBack (object sender, ValidationEventArgs args)
            {
                  throw new Exception("Submitted form is not valid: \r\n" + args.Message);
            }


Regards,
Mike Sharp

Thanks.  I was able to get it working in XMLSpy. I guess that MS isn't following the standards 100% (big surprise).