问题:

I have the following code, which I want to output xml data using the UTF-8 encoding format. but it always outputs data in UTF-16 :

        XslCompiledTransform xslt = new XslCompiledTransform();

            xslt.Load(XmlReader.Create(new StringReader(xsltString), new XmlReaderSettings()));

            StringBuilder sb = new StringBuilder();

            XmlWriterSettings writerSettings = new XmlWriterSettings();
            writerSettings.Encoding = Encoding.UTF8;
            writerSettings.Indent = true;

            xslt.Transform(XmlReader.Create(new StringReader(inputXMLToTransform)), XmlWriter.Create(sb, writerSettings));

回答1:

The XML output will contain a header that is based on the encoding of the stream, not the encoding specified in the settings. As strings are 16 bit unicode the encoding will be UTF-16. The workaround is to suppress the header and add it yourself instead:

writerSettings.OmitXmlDeclaration = true;

Then when you get the result from the StringBuilder:

string xml = "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\r\n" + sb.ToString();

回答2:

If you use a MemoryStream in place of the StringBuilder, the XmlWriter will respect the encoding you specify in the XmlWriterSettings, since the MemoryStream doesn't have an inherent encoding like the StringBuilder does.