C# XSLT in memory transformation - c#

I am currently running a live 'in-memory' XSLT transformation using the following code
XmlDocument XmlDoc = new XmlDocument();
XmlDoc.LoadXml(DS.GetXml());
XslCompiledTransform XsltTranformation = new XslCompiledTransform();
XsltTranformation.Load(#"C:\Users\maskew\Desktop\XSLTMapping.xsl");
Stream XmlStream = new MemoryStream();
XmlDoc.Save(XmlStream); //Stream is still blank after this line
XmlReader XmlRdr = XmlReader.Create(XmlStream);
MemoryStream stm = new MemoryStream();
XsltTranformation.Transform(XmlRdr, null, stm);
stm.Position = 1;
StreamReader sr = new StreamReader(stm);
string Output = sr.ReadToEnd();
Output = Output.Substring(2);
XmlDoc.LoadXml(Output);
XmlWriter XmlWrtr = XmlWriter.Create(#"C:\Users\maskew\Desktop\XmlMapping.xml");
XmlDoc.WriteTo(XmlWrtr);
XmlWrtr.Flush();
XmlWrtr.Close();
However, when I move the file from XmlDocument to MemoryStream in line 6 the stream contains nothing when checked and thus stopping the whole program from running.
Does anyone have any idea why this would be occuring?
UPDATED: The stream is containing information now, however the XmlReader object is receiving none of it still.

Try a simplyfying
XmlDocument xmlDoc = new XmlDocument();
xmlDoc.PreserveWhitespace = true;
xmlDoc.LoadXml(DS.GetXml());
// Create a writer for writing the transformed file.
XmlWriter writer = XmlWriter.Create(#"C:\Users\maskew\Desktop\XmlMapping.xml");
// Create and load the transform with script execution enabled.
XslCompiledTransform transform = new XslCompiledTransform();
XsltSettings settings = new XsltSettings();
settings.EnableScript = true;
transform.Load(#"C:\Users\maskew\Desktop\XSLTMapping.xsl", settings, null);
// Execute the transformation.
transform.Transform(xmlDoc, writer);

Try flushing and resetting the stream:
XmlDoc.Save(XmlStream);
XmlStream.Flush();
XmlStream.Position = 0;
XmlReader XmlRdr = XmlReader.Create(XmlStream);

Stream XmlStream = new MemoryStream();
How there can be something in it ? You are constructing an empty memoryStream...
EDIT :
You should try to clarify it by using the 'using' instruction (http://msdn.microsoft.com/fr-fr/library/yh598w02). Basically, class like StreamReader, MemeryStream, etc.. implement the IDisposable interface. If you wrap them with using, it will dispose the object automatically for you.

Related

how to save xmldocument to a stream

I've already written code to parse my xml file with an XmlReader so I don't want to rewrite it. I've now added encryption to the program. I have encrypt() and decrypt() functions which take an xml document and the encryption algorithm. I have a function that uses an xml reader to parse the file but now with the xml document I'm not sure how to create the xmlreader.
The question is how to save my xml document to a stream. I'm sure it's simple but I don't know anything about streams.
XmlDocument doc = new XmlDocument();
doc.PreserveWhitespace = true;
doc.Load(filep);
Decrypt(doc, key);
Stream tempStream = null;
doc.Save(tempStream); // <--- the problem is here I think
using (XmlReader reader = XmlReader.Create(tempStream))
{
while (reader.Read())
{ parsing code....... } }
You can try with MemoryStream class
XmlDocument xmlDoc = new XmlDocument( );
MemoryStream xmlStream = new MemoryStream( );
xmlDoc.Save( xmlStream );
xmlStream.Flush();//Adjust this if you want read your data
xmlStream.Position = 0;
//Define here your reading
Writing to a file:
static void Main(string[] args)
{
XmlDocument doc = new XmlDocument();
doc.LoadXml("<FTPSessionOptionInfo><HostName>ftp.badboymedia.ca</HostName></FTPSessionOptionInfo>");
using (StreamWriter fs = new StreamWriter("test.xml"))
{
fs.Write(doc.InnerXml);
}
}
I realize this is an old question, but thought it worth adding a method from this nice little blog post. This edges out some less performant methods.
private static XDocument DocumentToXDocumentReader(XmlDocument doc)
{
return XDocument.Load(new XmlNodeReader(doc));
}
try this
XmlDocument document= new XmlDocument( );
string pathTmp = "d:\somepath";
using( FileStream fs = new FileStream( pathTmp, FileMode.CreateNew ))
{
document.Save(pathTmp);
fs.Flush();
}

What's the non-deprecated alternative to XmlDataDocument and XslTransform?

I am modifying some legacy code to try to eliminate warnings. XmlDataDocument and XslTransform both generate warnings that they are obsolete. In the case of XslTransform the suggested replacement is XslCompiledTransform, but no replacement is suggested for XmlDataDocument.
How can I change this code to eliminate warnings in .NET 4:
var xmlDoc = new System.Xml.XmlDataDocument(myDataSet);
var xslTran = new System.Xml.Xsl.XslTransform();
xslTran.Load(new XmlTextReader(myMemoryStream), null, null);
var sw = new System.IO.StringWriter();
xslTran.Transform(xmlDoc, null, sw, null);
XDocument doc = new XDocument();
using (XmlWriter xw = doc.CreateWriter())
{
myDataSet.WriteXml(xw);
xw.Close();
}
XslCompiledTransform proc = new XslCompiledTransform();
using (XmlReader xr = XmlReader.Create(myMemoryStream))
{
proc.Load(xr);
}
string result;
using (StringWriter sw = new StringWriter())
{
proc.Transform(doc.CreateNavigator(), null, sw); // needs using System.Xml.XPath;
result = sw.ToString();
}
should do I think. Of course I have only used that MemoryStream for loading the stylesheet and the StringWriter for sending the transformation result to as you code snippet used those. Usually there are other input sources or output destinations like files, or streams or Textreader.
XMLDocument is really your main option. I'm not 100% sure what you're trying to do with the code block you've posted, but you can give something like this a shot:
public void DoThingsWithXml()
{
string strXdoc = src.GetTheXmlString(); // however it is you do it
XmlDocument xdoc = new XmlDocument();
xdoc.LoadXml(strXdoc);
// The other things you need to do
}

Xml Serialization / Deserialization Problem

After writing and reading an xml string to and from a stream, it ceases to be deserializable. The new string is clipped.
string XmlContent = getContentFromMyDataBase();
XmlSerializer xs = new XmlSerializer(typeof(MyObj));
MemoryStream ms = new MemoryStream();
StreamWriter sw = new StreamWriter(ms);
char[] ca = XmlContent.ToCharArray(); // still working up to this point.
ms.Position = 0;
sw.Write(ca);
StreamReader sr = new StreamReader(ms);
ms.Position = 0;
string XmlContentAgain = sr.ReadToEnd();
Console.WriteLine(XmlContentAgain); // (outputstring is too short.)
MyObj theObj = (MyObj)xs.Deserialize(ms); // Can't deserialize.
Any suggestions as to how to fix this or what is causing the problem? My only guess is that there is some form of encoding issue, but I wouldn't know how to go about finding/fixing it.
Additionally, myObj has a generic dictionary member, which typically isn't serializable, so I have stolen code from Paul Welter in order to serialize it.
Try flushing and disposing or even better simplify your code using a StringReader:
string xmlContent = getContentFromMyDataBase();
var xs = new XmlSerializer(typeof(MyObj));
using (var reader = new StringReader(xmlContent))
{
var theObj = (MyObj)xs.Deserialize(reader);
}
Note: The getContentFromMyDataBase method also suggests that you are storing XML in your database that you are deserializing back to an object. Don't.
You need to Flush or Close (closing implicitly flushes) the StreamWriter, or you cannot be sure it is done writing to the underlying stream. This is because it is doing some internal buffering.
Try this:
using(StreamWriter sw = new StreamWriter(ms))
{
char[] ca = XmlContent.ToCharArray(); // still working up to this point.
ms.Position = 0;
sw.Write(ca);
}
StreamReader sr = new StreamReader(ms);
ms.Position = 0;
string XmlContentAgain = sr.ReadToEnd();

XslCompiledTransform output as XPathDocument

I am trying to use a XslCompiledTransform, and use the output as a XPathDocument.
Any Ideas?
Mr. Jones's answer was very helpful for me, but I found that the last line didn't work. I ended up doing this:
XslCompiledTransform xsl = new XslCompiledTransform();
xsl.Load(filePath);
StringWriter stringWriter = new StringWriter();
XmlWriter xmlWriter = XmlTextWriter.Create(stringWriter);
xsl.Transform(xPathDoc, xmlWriter);
String newXml = stringWriter.ToString();
StringReader stringReader = new StringReader(newXml);
xPathDoc = new XPathDocument(stringReader);
(Here, xPathDoc is an XPathDocument that has already been initialized from an XmlReader.)
Send the transform to an XmlTextWriter based on a StringWriter. Then instance the XPathDocument by retreiving the XML string from the StringWriter.
var sw = new StringWriter();
var xtw = new XmlTextWriter(sw);
myTransform.Transform(myXml, xtw);
var xpd = new XPathDocument(sw.ToString());
Its not the most memory efficient mechanism but will be adequate for most needs. A similar approach would be use a MemoryStream instead of a StringWriter but its a little messy by comparison.
A slightly better form of David M. Anderson's answer is below: it does not suffer from potential resource leaks; otherwise it is the same.
private static XPathDocument TransformToXPathDocument(string styleSheetPath,
IXPathNavigable xPathDoc)
{
var xsl = new XslCompiledTransform();
xsl.Load(styleSheetPath);
using(var stringWriter = new StringWriter())
{
using(XmlWriter xmlWriter = XmlWriter.Create(stringWriter))
{
xsl.Transform(xPathDoc, xmlWriter);
}
using(var reader = new StringReader(stringWriter.ToString()))
{
return new XPathDocument(reader);
}
}
}

How to Convert a StreamReader into an XMLReader object in .Net 2.0/C#

Here's a quick question I've been banging my head against today.
I'm trying to convert a .Net dataset into an XML stream, transform it with an xsl file in memory, then output the result to a new XML file.
Here's the current solution:
string transformXML = #"pathToXslDocument";
XmlDocument originalXml = new XmlDocument();
XmlDocument transformedXml = new XmlDocument();
XslCompiledTransform transformer = new XslCompiledTransform();
DataSet ds = new DataSet();
string filepath;
originalXml.LoadXml(ds.GetXml()); //data loaded prior
StringBuilder sb = new StringBuilder();
XmlWriter writer = XmlWriter.Create(sb);
transformer.Load(transformXML);
transformer.Transform(originalXml, writer); //no need to select the node
transformedXml.LoadXml(sb.ToString());
transformedXml.Save(filepath);
writer.Close();
Here's the original code:
BufferedStream stream = new BufferedStream(new MemoryStream());
DataSet ds = new DataSet();
da.Fill(ds);
ds.WriteXml(stream);
StreamReader sr = new StreamReader(stream, true);
stream.Position = 0; //I'm not certain if this is necessary, but for the StreamReader to read the text the position must be reset.
XmlReader reader = XmlReader.Create(sr, null); //Problem is created here, the XmlReader is created with none of the data from the StreamReader
XslCompiledTransform transformer = new XslCompiledTransform();
transformer.Load(#"<path to xsl file>");
transformer.Transform(reader, null, writer); //Exception is thrown here, though the problem originates from the XmlReader.Create(sr, null)
For some reason in the transformer.Transform method, the reader has no root node, in fact the reader isn't reading anything from the StreamReader.
My questions is what is wrong with this code? Secondarily, is there a better way to convert/transform/store a dataset into XML?
Edit: Both answers were helpful and technically aku's was closer. However I am leaning towards a solution that more closely resembles Longhorn's after trying both solutions.
I'm not sure but it seems that you didn't reset position in stream before passing it to XmlReader. Try to seek at the beginning of your stream before trying to read from it. Also it may be necessary to close\flush stream after you wrote some data to it.
EDIT:
Just tried following code and it worked perfectly:
BufferedStream stream = new BufferedStream(new MemoryStream());
stream.Write(Encoding.ASCII.GetBytes("<xml>foo</xml>"), 0, "<xml>foo</xml>".Length);
stream.Seek(0, SeekOrigin.Begin);
StreamReader sr = new StreamReader(stream);
XmlReader reader = XmlReader.Create(sr);
while (reader.Read())
{
Console.WriteLine(reader.Value);
}
stream.Close();
You must select the root node. This doesn't use Datasets, but I use this function everyday and it works great.
System.Xml.XmlDocument orgDoc = new System.Xml.XmlDocument();
orgDoc.LoadXml(orgXML);
// MUST SELECT THE ROOT NODE
XmlNode transNode = orgDoc.SelectSingleNode("/");
System.Text.StringBuilder sb = new System.Text.StringBuilder();
XmlWriter writer = XmlWriter.Create(sb);
System.IO.StringReader stream = new System.IO.StringReader(transformXML);
XmlReader reader = XmlReader.Create(stream);
System.Xml.Xsl.XslCompiledTransform trans = new System.Xml.Xsl.XslCompiledTransform();
trans.Load(reader);
trans.Transform(transNode, writer);
XmlDocument doc = new XmlDocument();
doc.LoadXml(sb.ToString());
return doc;
please look it and use..
using (MemoryStream memStream = new MemoryStream())
{
memStream.Write(Encoding.UTF8.GetBytes(xmlBody), 0, xmlBody.Length);
memStream.Seek(0, SeekOrigin.Begin);
using (StreamReader reader = new StreamReader(memStream))
{
// xml reader setting.
XmlReaderSettings xmlReaderSettings = new XmlReaderSettings()
{
IgnoreComments = true,
IgnoreWhitespace = true,
};
// xml reader create.
using (XmlReader xmlReader = XmlReader.Create(reader, xmlReaderSettings))
{
XmlSerializer xmlSerializer = new XmlSerializer(typeof(LoginInfo));
myObject = (LoginInfo)xmlSerializer.Deserialize(xmlReader);
}
}
}

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