How to write a comment to an XML file when using the XmlSerializer?

Question

I have an object Foo which I serialize to an XML stream.

public class Foo {
  // The application version, NOT the file version!
  public string Version {get         


        

Answer 1

Probably late to the party but I had problems when I was trying to deserialize using Kirill Polishchuk solution. Finally I decided to edit the XML after serializing it and the solution looks like:

public static void WriteXml(object objectToSerialize, string path)
{
    try
    {
        using (var w = new XmlTextWriter(path, null))
        {
            w.Formatting = Formatting.Indented;
            var serializer = new XmlSerializer(objectToSerialize.GetType());
            serializer.Serialize(w, objectToSerialize);
        }

        WriteComments(objectToSerialize, path);
    }
    catch (Exception e)
    {
        throw new Exception($"Could not save xml to path {path}. Details: {e}");
    }
}

public static T ReadXml(string path) where T:class, new()
{
    if (!File.Exists(path))
        return null;
    try
    {
        using (TextReader r = new StreamReader(path))
        {
            var deserializer = new XmlSerializer(typeof(T));
            var structure = (T)deserializer.Deserialize(r);
            return structure;
        }
    }
    catch (Exception e)
    {
        throw new Exception($"Could not open and read file from path {path}. Details: {e}");
    }
}

private static void WriteComments(object objectToSerialize, string path)
{
    try
    {
        var propertyComments = GetPropertiesAndComments(objectToSerialize);
        if (!propertyComments.Any()) return;

        var doc = new XmlDocument();
        doc.Load(path);

        var parent = doc.SelectSingleNode(objectToSerialize.GetType().Name);
        if (parent == null) return;

        var childNodes = parent.ChildNodes.Cast().Where(n => propertyComments.ContainsKey(n.Name));
        foreach (var child in childNodes)
        {
            parent.InsertBefore(doc.CreateComment(propertyComments[child.Name]), child);
        }

        doc.Save(path);
    }
    catch (Exception)
    {
        // ignored
    }
}

private static Dictionary GetPropertiesAndComments(object objectToSerialize)
{
    var propertyComments = objectToSerialize.GetType().GetProperties()
        .Where(p => p.GetCustomAttributes(typeof(XmlCommentAttribute), false).Any())
        .Select(v => new
        {
            v.Name,
            ((XmlCommentAttribute) v.GetCustomAttributes(typeof(XmlCommentAttribute), false)[0]).Value
        })
        .ToDictionary(t => t.Name, t => t.Value);
    return propertyComments;
}

[AttributeUsage(AttributeTargets.Property)]
public class XmlCommentAttribute : Attribute
{
    public string Value { get; set; }
}