c# - Formatting string in XML format and remove invalid attribute characters

Question

I've a string say "<Node a="<b>">". I need to escape only the data and parse this string as a node in XMLWriter. Hence how to escape only the attribute value "<" and note the XML structure's "<".

Answer 1

using (var writer = XmlWriter.Create(Console.Out))
{
    writer.WriteStartElement("Node");
    writer.WriteAttributeString("a", "<b>");
}

Output <Node a="&lt;b&gt;" />

---

Firstly you should parse the string. Since this is not valid xml, you can't use an xml parser. You can try HtmlAgilityPack. Then you can write the values with xml writer.

string s = "<Node a="<b>">";

var doc = new HtmlAgilityPack.HtmlDocument();
doc.LoadHtml(s);

var node = doc.DocumentNode.FirstChild;
var attr = node.Attributes[0];

using (var writer = XmlWriter.Create(Console.Out))
{
    writer.WriteStartElement(node.Name);
    writer.WriteAttributeString(attr.Name, attr.Value);
}