向 XElement 添加 XML 声明

Question

I created a big XML document using XElement and XAttribute. I did it by adding the attributes to the elements and adding elements to elements.

Like this:

// root node: PhysicalProperty
XElement PhysicalProperty = new XElement("PhysicalProperty");

// PhysicalProperty child element: Management
XElement Management = new XElement("Management");
XAttribute ManagementOrganizationName = new XAttribute("OrganizationName", property.Company.Name);
XAttribute ManagementManagementID = new XAttribute("ManagementID", property.Company.CompanyID);
Management.Add(ManagementOrganizationName);
Management.Add(ManagementManagementID);
PhysicalProperty.Add(Management);

My XML has a lot of elements. However, I noticed that it did not created the xml declaration:

<?xml version="1.0" encoding="UTF-8"?>

It looks like I should have created a XDocument. How can I create the XDocument and add my root element (PhysicalProperty) to the XDocument? Is it possible?

Answer 1

您需要将new XDeclaration(...)传递给XDocument构造函数，然后是根元素。

Answer 2

You must start with an XDocument, which comes with a default declaration member with utf-8 encoding. If you need to, you could replace Declaration with a new instance of this.

var fi = new FileInfo(@"[MyFileName]");
var cultureName = "en-CA";
XDocument doc = XDocument.Load(fi.FullName, LoadOptions.PreserveWhitespace);
var language = doc.Descendants()
        .Where(t => t.Name.LocalName == "Language")
        .FirstOrDefault();

if (language != null && language.Value != cultureName)
{
    language.SetValue(cultureName);
    File.WriteAllText(fi.FullName
        , $"{doc.Declaration}{doc.ToString()}"
        , encoding: Encoding.UTF8);
}

From the document you can search, browse, or create items. Once you need to store the contents of the XML document as such, with its declaration, you can simply concatenate the declaration when saving the content. The content of the document already includes a line break to incorporate the declaration.