Asp – Uploading an XML file, referencing an XSD, in ASP.Net

asp.netxmlxml-validationxsd

I have an XML file which is being uploaded to an ASP.Net page via the normal file upload control. When it gets up, I am attempting to validate and deserialize the XML. However, the code below is really very handy for validating an XML file which references it's XSD like this:

xsi:schemaLocation="someurl ..\localSchemaPath.xsd"

However, if I upload this XML file, only the XML file gets uploaded, so ..\localSchemaPath.xsd doesn't exist, so it can't validate.

Even if I stored the XSD locally, it still wouldn't be quite right as the XML file could be written with a schema location like:

xsi:schemaLocation="someurl ..\localSchemaPath.xsd"

or
xsi:schemaLocation="someurl localSchemaPath.xsd"
or
xsi:schemaLocation="someurl ………………\localSchemaPath.xsd"
if it so wished.

Dilemma!

(For the purposes of this question, I have pinched the code below from: Validating an XML against referenced XSD in C#) 

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);
    }
}

Best Answer

Here is a chunk of code I use to validate xml with a local schema:

string errors = string.Empty;

try
{
    XmlSchemaSet schemas = new XmlSchemaSet();
    schemas.Add(string.Empty, Page.MapPath("~/xml/Schema.xsd"));
    XmlDocument doc = new XmlDocument();
    doc.Schemas = schemas;
    doc.Load(Page.MapPath("~/xml/sampleXML.xml"));
    //use this line instead of the one above for a string in memory.
    //doc.InnerXml = xmlToValidate;  
    ValidationEventHandler validator = delegate(object send, ValidationEventArgs ve)
                                           {
                                               errors += "\n" + ve.Severity + ": " + ve.Message;
                                           };

    doc.Validate(validator);
}
catch (XmlException xe)
{
    errors += "\n" + xe.Message;
}
catch (XmlSchemaValidationException xe)
{
    errors += "\n" + xe.Message;
}
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