添加XML声明字符串XML

Question

我有，看起来像..

<Root> 
<Data>Nack</Data> 
<Data>Nelly</Data> 
</Root> 

我想补充"<?xml version=\"1.0\"?>"这个字符串的一些XML数据。然后将xml保存为一个字符串。

我尝试了一些东西..

这种断裂，失去原有的XML字符串

myOriginalXml="<?xml version=\"1.0\"?>" + myOriginalXml; 

，这并不做任何事，只是保持原始的XML数据，不附加任何声明。

XmlDocument doc = new XmlDocument(); 
       doc.LoadXml(myOriginalXml); 
       XmlDeclaration declaration = doc.CreateXmlDeclaration("1.0", "UTF-8","no"); 
       StringWriter sw = new StringWriter(); 
       XmlTextWriter tx = new XmlTextWriter(sw); 
       doc.WriteTo(tx); 
       string xmlString = sw.ToString(); 

这也似乎不会有任何效果..

XmlDocument doc = new XmlDocument(); 
       doc.LoadXml(myOriginalXml); 
       XmlDeclaration declaration = doc.CreateXmlDeclaration("1.0", "UTF-8", "no"); 
       MemoryStream xmlStream = new MemoryStream(); 
       doc.Save(xmlStream); 
       xmlStream.Flush(); 
       xmlStream.Position = 0; 
       doc.Load(xmlStream); 
       StringWriter sw = new StringWriter(); 
       XmlTextWriter tx = new XmlTextWriter(sw); 
       doc.WriteTo(tx); 
       string xmlString = sw.ToString(); 

Answer 1

使用一个xmlwritersettings达到节省上更大的控制权。该XmlWriter.Create接受设置（而不是默认的构造器）

var myOriginalXml = @"<Root> 
          <Data>Nack</Data> 
          <Data>Nelly</Data> 
          </Root>"; 
    var doc = new XmlDocument(); 
    doc.LoadXml(myOriginalXml); 
    var ms = new MemoryStream(); 
    var tx = XmlWriter.Create(ms, 
       new XmlWriterSettings { 
          OmitXmlDeclaration = false, 
          ConformanceLevel= ConformanceLevel.Document, 
          Encoding = UTF8Encoding.UTF8 }); 
    doc.Save(tx); 
    var xmlString = UTF8Encoding.UTF8.GetString(ms.ToArray());