using System;

using System.Xml.Serialization;

using System.Xml.Schema;

using System.Xml;

using System.IO;

public class Program

{

    public static void Main()

    {

        var xsd = new XmlSchemaSet();

        xsd.Add(

            XmlSchema.Read(new StringReader(

        """

        <?xml version='1.0'?>

​

               <xs:schema

                    targetNamespace = "http://example.org/scratch"

                    xmlns           = "http://example.org/scratch"

                    xmlns:xs        = "http://www.w3.org/2001/XMLSchema">

​

               <xs:element name="root" type="xs:token"/>

​

               </xs:schema>

        """), null)

        );

​

        var xdoc = 

        """

        <?xml version='1.0'?>

​

           <pre:root xmlns:pre="http://example.org/scratch">   abc   </pre:root>

        """;

        var xmlReaderSettings = new XmlReaderSettings

        {

            CheckCharacters = true,

            DtdProcessing   = DtdProcessing.Prohibit,

            Schemas         = xsd,

            ValidationType  = ValidationType.Schema,

        };

        using var xreader1 = XmlReader.Create(new StringReader(xdoc), xmlReaderSettings);

        xreader1.MoveToContent();

        xreader1.ReadElementContentAsString().Length.Dump();

        using var xreader2 = XmlReader.Create(new StringReader(xdoc), xmlReaderSettings);

        var r = (Root)new XmlSerializer(typeof(Root)).Deserialize(xreader2);

        r.Value.Length.Dump();

    }

}

​

[XmlRoot(Namespace = "http://example.org/scratch", ElementName = "root")]

public class Root

{

    [XmlText(DataType = "token")]

    public string Value {get;set;}

}

​