XML serialization and deserialization objects containing invalid chars in properties

Question

I know this was asked before for many times but still don't see a good solution.
There is an object like this:

public class DTO
{
    public string Value;
}

I need to serialize it in the Exporter app and then deserialize in the Importer.
Object's Value may contain characters who are not valid for XML (e.x. 0x8). I need to either let Exporter remove such chars or let Importer successfully load object containing the chars. I wouldn't like to clean up objects before serialization because I have tens of them with tens string properties each.

Importer side. If I enable CheckCharacters here then I'll get error on serialization step. I don't see a way to custom control all strings at one spot. If I disable it then the XML will contain invalid char.

XmlWriterSettings xmlWriterSettings = new XmlWriterSettings { CheckCharacters = false };
XmlSerializer xmlSerializer = new XmlSerializer(typeof(DTO));
StringBuilder sb = new StringBuilder();
DTO dto = new DTO { Value = Convert.ToChar(0x08).ToString() };

using (XmlWriter xmlWriter = XmlWriter.Create(sb, xmlWriterSettings))
{
    xmlSerializer.Serialize(xmlWriter, dto); 
    xmlWriter.Flush();
    xmlWriter.Close();
}

Ok, if I let invalid char go to XML then there is no way to handle it on Import side. Even if CheckCharacters = false, the error occurs on Deserialize() call:

var _reader = XmlReader.Create(File.OpenText(path), new XmlReaderSettings() { CheckCharacters = false });
_reader.MoveToContent();
var outerXml = _reader.ReadOuterXml();
xmlSerializer.Deserialize(new StringReader(outerXml)); <== getting error here

Is there a way to remove invalid chars in either step and let the object exported/imported without errors?

Can you provide an example of data containing the invalid characters? — Robert Harvey, Apr 18 '19 at 20:20
Character 0x08 is a backspace. Why would that be present in an XML file? — Robert Harvey, Apr 18 '19 at 20:23
@RobertHarvey I'm getting data from many customers and they may contain anything. They may have come from imports, manual updates, programs etc - not only produced by manual input. I'd like to convert them as-is or be able to remove all invalid chars in a single spot. — LINQ2Vodka, Apr 18 '19 at 20:35
Alright. Have you reviewed the answers in the link I posted above? — Robert Harvey, Apr 18 '19 at 20:36
Non of them helps according to the task above unfortunately. — LINQ2Vodka, Apr 18 '19 at 21:55

score 1 · Answer 1 · answered Apr 18 '19 at 22:25

That was my bad :(
In here:

var outerXml = _reader.ReadOuterXml();
xmlSerializer.Deserialize(new StringReader(outerXml)); <== getting error here

xmlSerializer was actually using an implicitly created internal XmlReader which did check characters. All I had to do four hours ago was:

xmlSerializer.Deserialize(_reader);

score 0 · Answer 2 · answered Apr 18 '19 at 21:57

I'm not saying this is a great solution but code below will remove non UTF8 characters when serializing :

    public class DTO
    {
        private string _value { get; set; }
        public string Value
        {
            get { return Encoding.UTF8.GetString(_value.Select(x => (byte)((int)x)).ToArray()); }
            set { _value = value; }
        }

    }

XML serialization and deserialization objects containing invalid chars in properties

2 Answers2