How do I return Xml with declaration using an ActionResult in ASP.NET MVC?

Question

I'm unable to attach a xml declaration while returning xml using Action Result. I can see it being included while debugging till line at which it returns xml in below code but doesn't not show up on the web.

What I am doing currently:

1. Getting Xml from Sql Server using XML PATH.

2. Returning xml string using XML Reader:

   public XmlDocumentResult XmlData()
   {
       String s = "<?xml version=\"1.0\" encoding=\"utf-8\" ?>" + "\n" +  this.GetData();
       byte[] encodedString = Encoding.UTF8.GetBytes(s);
       MemoryStream ms = new MemoryStream(encodedString);
       ms.Flush();
       ms.Position = 0;
       XmlDocument doc = new XmlDocument();
       doc.Load(ms);           
       return new XmlDocumentResult { XmlDocument = doc };
   }
   
   public class XmlDocumentResult : ContentResult
    {
        public XmlDocument XmlDocument { get; set; }
   
        public override void ExecuteResult(ControllerContext context)
        {
            if (XmlDocument == null)
                return;
   
            Content = XmlDocument.OuterXml;
            ContentType = "text/xml";
            base.ExecuteResult(context);
        }
    }
   

I have tried following code snippets from Stackoverflow:

XmlDeclaration xmldecl;
xmldecl = xmlDocument.CreateXmlDeclaration("1.0", "UTF-8", null);
XmlElement root = xmlDocument.DocumentElement;
xmlDocument.InsertBefore(xmldecl, root);


XmlNode docNode = xml.CreateXmlDeclaration("1.0", "UTF-8", null);
xml.AppendChild(docNode);

Answer 1

Maybe try this:

public IActionResult Index()
{
    // you need to convert your xml to string
    var xmlString = "xml content..";
    return this.Content(xmlString, "text/xml");
}

See https://learn.microsoft.com/en-us/previous-versions/aspnet/web-frameworks/dd492713%28v%3dvs.100%29