你必须以某种方式解析内容。我发现使用LINQ是最简单的方法。同样，这完全取决于您的具体场景。下面是一个使用LINQ格式化输入XML字符串的示例。

string FormatXml(string xml)
{
     try
     {
         XDocument doc = XDocument.Parse(xml);
         return doc.ToString();
     }
     catch (Exception)
     {
         // Handle and throw if fatal exception here; don't just ignore them
         return xml;
     }
 }

[为简洁起见，省略使用语句]

如何漂亮地打印XML(不幸的是，该链接现在返回404:()

链接中的方法以XML字符串作为参数，并返回格式良好(缩进)的XML字符串。

我只是从链接中复制了示例代码，以使这个回答更全面和方便。

public static String PrettyPrint(String XML)
{
    String Result = "";

    MemoryStream MS = new MemoryStream();
    XmlTextWriter W = new XmlTextWriter(MS, Encoding.Unicode);
    XmlDocument D   = new XmlDocument();

    try
    {
        // Load the XmlDocument with the XML.
        D.LoadXml(XML);

        W.Formatting = Formatting.Indented;

        // Write the XML into a formatting XmlTextWriter
        D.WriteContentTo(W);
        W.Flush();
        MS.Flush();

        // Have to rewind the MemoryStream in order to read
        // its contents.
        MS.Position = 0;

        // Read MemoryStream contents into a StreamReader.
        StreamReader SR = new StreamReader(MS);

        // Extract the text from the StreamReader.
        String FormattedXML = SR.ReadToEnd();

        Result = FormattedXML;
    }
    catch (XmlException)
    {
    }

    MS.Close();
    W.Close();

    return Result;
}

你必须以某种方式解析内容。我发现使用LINQ是最简单的方法。同样，这完全取决于您的具体场景。下面是一个使用LINQ格式化输入XML字符串的示例。

string FormatXml(string xml)
{
     try
     {
         XDocument doc = XDocument.Parse(xml);
         return doc.ToString();
     }
     catch (Exception)
     {
         // Handle and throw if fatal exception here; don't just ignore them
         return xml;
     }
 }

[为简洁起见，省略使用语句]

格式化一个XML文件，使它在c#中看起来更好

// Format the XML text.
StringWriter string_writer = new StringWriter();
XmlTextWriter xml_text_writer = new XmlTextWriter(string_writer);
xml_text_writer.Formatting = Formatting.Indented;
xml_document.WriteTo(xml_text_writer);

// Display the result.
txtResult.Text = string_writer.ToString();

使用XmlTextWriter……

public static string PrintXML(string xml)
{
    string result = "";

    MemoryStream mStream = new MemoryStream();
    XmlTextWriter writer = new XmlTextWriter(mStream, Encoding.Unicode);
    XmlDocument document = new XmlDocument();

    try
    {
        // Load the XmlDocument with the XML.
        document.LoadXml(xml);

        writer.Formatting = Formatting.Indented;

        // Write the XML into a formatting XmlTextWriter
        document.WriteContentTo(writer);
        writer.Flush();
        mStream.Flush();

        // Have to rewind the MemoryStream in order to read
        // its contents.
        mStream.Position = 0;

        // Read MemoryStream contents into a StreamReader.
        StreamReader sReader = new StreamReader(mStream);

        // Extract the text from the StreamReader.
        string formattedXml = sReader.ReadToEnd();

        result = formattedXml;
    }
    catch (XmlException)
    {
        // Handle the exception
    }

    mStream.Close();
    writer.Close();

    return result;
}

对我来说，最简单的解决方法就是:

        XmlDocument xmlDoc = new XmlDocument();
        StringWriter sw = new StringWriter();
        xmlDoc.LoadXml(rawStringXML);
        xmlDoc.Save(sw);
        String formattedXml = sw.ToString();