C# 如何构建xml节并保存到文件（本身不是有效的xml文档）

我试图构建XML文档的一小部分，并将其包含在最终文档中。 使用

XDocument

时，我遇到一个异常：

“此操作将创建结构不正确的文档。”

因为我的片段有多个“根”节点

由于该文件将包含在一个较大的文档中，因此我的基本元素将不会出现在最终文档的根目录中

XDocument constsDocument = new XDocument(
    new XComment($" Consts section generated on {DateTime.Now} "),
    new XComment($" First group of constants. "),
    FirstTextConsts(MyFirstCollection),
    new XComment($" Refrigerant constants. "),
    SecondTextConsts(MySecondCollection)
    );
// To avoid xml file starting with <?xml version="1.0" encoding="utf-8"?> use stringbuilder and StreamWriter.
StringBuilder sb = new StringBuilder();
XmlWriterSettings xws = new XmlWriterSettings
{
    OmitXmlDeclaration = true,
    Indent = true
};
using (XmlWriter xw = XmlWriter.Create(sb, xws))
{
    constsDocument.Save(xw);
}
System.IO.StreamWriter file = new System.IO.StreamWriter(_outputFileName);
file.WriteLine(sb.ToString()); 
file.Close();

在写入文件之前，我剥离元素：

    file.WriteLine(sb.ToString().Replace("<root>" + Environment.NewLine, "").Replace(Environment.NewLine + "</root>", ""));

file.WriteLine（sb.ToString（）.Replace（“+Environment.NewLine，”）.Replace（Environment.NewLine+”，”）；

您可以声明希望XML只是一个片段，然后从XDocument切换到XMLDocument：

XmlDocument constDocument = new XmlDocument();
constDocument.CreateComment(" Consts section generated on {DateTime.Now} ");
constDocument.CreateComment(" First group of constants. ");
FirstTextConsts(MyFirstCollection); // Need to be adapted
constDocument.CreateComment(" Refrigerant constants. ");
SecondTextConsts(MySecondCollection); // Need to be adapted
XmlDocumentFragment fragDocument = constDocument.CreateDocumentFragment();
fragDocument.InnerXml = "<const>fragment</const><const>fragment2</const>"; // Need to be adapted

StringBuilder sb = new StringBuilder();
XmlWriterSettings xws = new XmlWriterSettings
{
    ConformanceLevel = ConformanceLevel.Fragment,
    OmitXmlDeclaration = true,
    Indent = true
};
using (XmlWriter xw = XmlWriter.Create(sb, xws))
{
    fragDocument.WriteContentTo(xw);
}
System.IO.StreamWriter file = new System.IO.StreamWriter(_outputFileName);
file.WriteLine(sb.ToString()); 
file.Close();

XmlDocument constDocument=新的XmlDocument（）；
CreateComment（“在{DateTime.Now}上生成的Consts节”）；
CreateComment（“第一组常量”）；
FirstTextConsts（MyFirstCollection）；//需要调整
constDocument.CreateComment（“制冷剂常量”）；
SecondTextConsts（MySecondCollection）；//需要调整
XmlDocumentFragment fragDocument=constDocument.CreateDocumentFragment（）；
fragDocument.InnerXml=“fragment2”//需要调整
StringBuilder sb=新的StringBuilder（）；
xws=新的XmlWriterSettings
{
ConformanceLevel=ConformanceLevel.Fragment，
OmitXmlDeclaration=true，
缩进=真
};
使用（xmlwriterxw=XmlWriter.Create（sb，xws））
{
fragDocument.writeContento（xw）；
}
System.IO.StreamWriter file=新的System.IO.StreamWriter（_outputFileName）；
file.WriteLine（sb.ToString（））；
file.Close（）；

或添加算术根元素：

    file.WriteLine(sb.ToString().Replace("<root>" + Environment.NewLine, "").Replace(Environment.NewLine + "</root>", ""));

"<aritificialroot>" + fragment + "</aritificialroot>"

“”+fragment+“”

无法创建无效的

XDocument

（由于有多个“根”节点）。因此，您需要创建一个节点列表，并将其写入文档片段

var constsDocument = new List<XNode> {
           new XComment($" Consts section generated on {DateTime.Now} "),
           new XComment($" First group of constants. "),
           new XElement("example"),
           new XComment($" Refrigerant constants. "),
           new XElement("another")
};
// To avoid xml file starting with <?xml version="1.0" encoding="utf-8"?> use stringbuilder and StreamWriter.
StringBuilder sb = new StringBuilder();
XmlWriterSettings xws = new XmlWriterSettings
{
    OmitXmlDeclaration = true,
    Indent = true,
    ConformanceLevel = ConformanceLevel.Fragment
};
using (XmlWriter xw = XmlWriter.Create(sb, xws))
{
    foreach (var element in constsDocument)
    {
        element.WriteTo(xw);
    }
}
System.IO.StreamWriter file = new System.IO.StreamWriter(_outputPath);
file.WriteLine(sb.ToString());
file.Close();

---

我编辑了我的问题，以说明在文档创建过程中调用的两种方法。正如你所建议的那样，它们在对象初始值设定项中不起作用？@TheRoadrunner我刚刚用一个可能的解决方案更新了我的答案，以使用返回多个

XElement

实例的两个方法。非常感谢你的更新。它按照您建议的方式工作。我最终返回到XDocument并添加了一个虚假元素，然后在创建文件之前将其从stringbuilder中删除。原因是您的sugested解决方案只支持在第一层调用我的助手方法，而在现实生活中，我也在更深的层调用助手方法。

var constsDocument = new List<XNode> {
           new XComment($" Consts section generated on {DateTime.Now} "),
           new XComment($" First group of constants. "),
           new XElement("example"),
           new XComment($" Refrigerant constants. "),
           new XElement("another")
};
// To avoid xml file starting with <?xml version="1.0" encoding="utf-8"?> use stringbuilder and StreamWriter.
StringBuilder sb = new StringBuilder();
XmlWriterSettings xws = new XmlWriterSettings
{
    OmitXmlDeclaration = true,
    Indent = true,
    ConformanceLevel = ConformanceLevel.Fragment
};
using (XmlWriter xw = XmlWriter.Create(sb, xws))
{
    foreach (var element in constsDocument)
    {
        element.WriteTo(xw);
    }
}
System.IO.StreamWriter file = new System.IO.StreamWriter(_outputPath);
file.WriteLine(sb.ToString());
file.Close();

var constsDocument = new List<IEnumerable<XNode>> {
    new [] { new XComment($" Consts section generated on {DateTime.Now} ") },
    new [] { new XComment($" First group of constants. ") },
    FirstTextConsts(MyFirstCollection),
    new [] { new XComment($" Refrigerant constants. ") },
    SecondTextConsts(MySecondCollection)
);

foreach (var element in constsDocument.SelectMany(n => n))