Develop Reference

XSLT parameters from C# (XML to XML)

I need to transform an XML file to another XML filtered. I want to use XSLT/C# to do this operation.
My source code in C# will execute the XSLT file with a list of parameter (I'm using XslCompiledTransform class).
My question is : how in XSLT language I can parse all parameters transmited from the C# to filter the output XML file.
Example : a list of car
<cars>
<car brand="Audi" model="A4/>
<car brand="Audi" model="A6/>
<car brand="Audi" model="A7/>
<car brand="Volvo" model="V40" />
<car brand="Volvo" model="V60" />
<car brand="Honda" model="Civic" />
<car brand="Mercedes" model="Class E" />
</cars>
a simple XSLT with brandsSelect parameter
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0">
<xsl:param name="brandsSelect"></xsl:param>
<xsl:template match="#* | node()">
<xsl:copy>
<xsl:apply-templates select="#* | node()"/>
</xsl:copy>
</xsl:template>
</xsl:stylesheet>
In my C# source code, I populate my variable :
brandsSelect = Volvo, Honda
Expected result :
<cars>
<car brand="Volvo" model="V40" />
<car brand="Volvo" model="V60" />
<car brand="Honda" model="Civic" />
</cars>
Thanks for your help !

What you could do (in XSLT 1.0 which is what XSLTCompiledTransform implements) is to do a string test to see if the parameter "contains" the brand attribute:
<xsl:template match="cars">
<xsl:copy>
<xsl:apply-templates select="car[contains($brandsSelect, #brand)]" />
</xsl:copy>
</xsl:template>
However, this will fail if one brand happens to be a substring of another (For example, if "Laudi" was brand as well as "Audi"
So, to make it robust, try this XSLT
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0">
<xsl:output method="xml" indent="yes" />
<xsl:param name="brandsSelect">Volvo,Honda</xsl:param>
<xsl:variable name="brandMatcher" select="concat(',', $brandsSelect, ',')" />
<xsl:template match="#* | node()">
<xsl:copy>
<xsl:apply-templates select="#* | node()"/>
</xsl:copy>
</xsl:template>
<xsl:template match="cars">
<xsl:copy>
<xsl:apply-templates select="car[contains($brandMatcher, concat(',', #brand, ','))]" />
</xsl:copy>
</xsl:template>
</xsl:stylesheet>
It is important to note, the value of the brandsSelect should not contain any spaces between the brands, only commas.

How to transform XML using XSLT based on external parameter?

I have incoming XML message and each message have different schema. I want to transform that request into another schema using C#.Net as my XSLT processor. Here is simplified scenario of the situation I have.
Incoming request:
<?xml version="1.0" encoding="utf-8"?>
<Request xmlns="http://www.example.com/api">
<SourceId>SourceId1</SourceId>
<RequestId>RequestId1</RequestId>
<StatusEvent>
<TenderId>TenderId1</TenderId>
<EventCode>TENDER_STARTED</EventCode>
</StatusEvent>
</Request>
Translate to:
<?xml version="1.0" encoding="utf-8"?>
<TransactionStatus xmlns="http://www.example1.com/api">
<RequestId>RequestId1</RequestId>
<TransactionId>TenderId1</TransactionId>
<Event>TRANSACTION_STARTED</Event>
</TransactionStatus>
Incoming request:
<?xml version="1.0" encoding="utf-8"?>
<Response xmlns="http://www.example.com/api">
<SourceId>SourceId1</SourceId>
<RequestId>RequestId1</RequestId>
<TenderCreated>
<TenderId>TenderId1</TenderId>
</TenderCreated>
</Response>
Translate to:
<?xml version="1.0" encoding="utf-8"?>
<TransactionStarted xmlns="http://www.example1.com/api">
<RequestId>RequestId1</RequestId>
<TransactionId>TenderId1</TransactionId>
</TransactionStarted>
Here is the XSLT I'm currently using to achieve above result,
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:ns0="http://www.example.com/api"
xmlns:xs="http://www.w3.org/2001/XMLSchema" exclude-result-prefixes="ns0 xs">
<xsl:output method="xml" encoding="UTF-8" indent="yes"/>
<xsl:template match="text()"/>
<xsl:template match="ns0:StatusEvent[1]">
<TransactionStatus
xmlns="http://www.example1.com/api">
<RequestId>
<xsl:value-of select="//ns0:RequestId"/>
</RequestId>
<TransactionId>
<xsl:value-of select="ns0:TenderId"/>
</TransactionId>
<Event>
<xsl:value-of select="ns0:EventCode"/>
</Event>
</TransactionStatus>
</xsl:template>
<xsl:template match="ns0:TenderCreated[1]">
<TransactionStarted
xmlns="http://www.example1.com/api">
<RequestId>
<xsl:value-of select="//ns0:RequestId"/>
</RequestId>
<TransactionId>
<xsl:value-of select="ns0:TenderId"/>
</TransactionId>
</TransactionStarted>
</xsl:template>
</xsl:stylesheet>
So Here is the two questions I have,
For the current scenario I'm getting correct result but, is there any better way to achieve this?
For some of the incoming request, I want to select template based on external parameter, how do I achieve that?
Update: More clarification on second question,
e.g: In 2nd Incoming request I might have TenderUpdated instead of TenderCreated and for that I want to translate that into either TransactionUpdated or TransactionCanceled depends on external string parameter.
so If incoming request is like,
<?xml version="1.0" encoding="utf-8"?>
<Response xmlns="http://www.example.com/api">
<SourceId>SourceId1</SourceId>
<RequestId>RequestId1</RequestId>
<TenderUpdated>
<TenderId>TenderId1</TenderId>
</TenderUpdated>
</Response>
And parameter passed is Update, translate to
<?xml version="1.0" encoding="utf-8"?>
<TransactionUpdated xmlns="http://www.example1.com/api">
<RequestId>RequestId1</RequestId>
<TransactionId>TenderId1</TransactionId>
<Update/>
</TransactionUpdated>
And if parameter passed is Cancel , translate to
<?xml version="1.0" encoding="utf-8"?>
<TransactionCanceled xmlns="http://www.example1.com/api">
<RequestId>RequestId1</RequestId>
<TransactionId>TenderId1</TransactionId>
<Cancel/>
</TransactionCanceled>
This is simplified scenario, actual message have more xml tag and TransactionUpdated and TransactionCanceled differs much.

If you know all result elements should be in the namespace http://www.example1.com/api then you can put that on the xsl:stylesheet e.g.
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns="http://www.example1.com/api"
xmlns:ns0="http://www.example.com/api"
xmlns:xs="http://www.w3.org/2001/XMLSchema" exclude-result-prefixes="ns0 xs">
As for the parameter, declare it as
<xsl:param name="transactionName" select="'Updated'"/>
and when you want to create an element using that parameter don't use a literal result element but xsl:element instead:
<xsl:element name="Transaction{$transactionName}">...</xsl:element>
Unfortunately in XSLT 1.0 the use of parameter or variables references inside of patterns is not allowed so to handle the condition you can only write a template matching on the element name and then you need to use xsl:choose/xsl:when to handle the different element names. Here is an example that you can hopefully extend:
<xsl:transform
xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
version="1.0"
xmlns:api="http://www.example.com/api"
xmlns="http://www.example1.com/api"
exclude-result-prefixes="api">
<xsl:param name="transactionName" select="'Update'"/>
<xsl:output indent="yes"/>
<xsl:template match="api:Response">
<xsl:element name="Transaction{$transactionName}">
<xsl:apply-templates select="api:RequestId | api:TenderUpdated/api:TenderId"/>
<xsl:choose>
<xsl:when test="$transactionName = 'Update'">
<Update/>
</xsl:when>
<xsl:when test="$transactionName = 'Cancel'">
<Cancel/>
</xsl:when>
</xsl:choose>
</xsl:element>
</xsl:template>
<xsl:template match="api:RequestId">
<RequestId>
<xsl:apply-templates/>
</RequestId>
</xsl:template>
<xsl:template match="api:TenderId">
<TransactionId>
<xsl:apply-templates/>
</TransactionId>
</xsl:template>
</xsl:transform>
Online at http://xsltransform.net/94rmq5R.
If there are lots of differences between the input formats then I might be tempted to handle them by different stylesheets. If that is not possible then it might make sense to branch in the template for the root and use modes on templates to distinguish the handling e.g.
<xsl:template match="api:Response">
<xsl:choose>
<xsl:when test="$transactionName = 'Update'">
<xsl:apply-templates select="." mode="update"/>
</xsl:when>
<xsl:when test="$transactionName = 'Cancel'">
<xsl:apply-templates select="." mode="cancel"/>
</xsl:when>
</xsl:choose>
</xsl:element>
</xsl:template>
<xsl:template match="api:Response" mode="update">
<TransactionUpdate>
<xsl:apply-templates select="api:Foo | api:Bar" mode="update"/>
<Update/>
<TransactionUpdate>
</xsl:template>
<!-- now add templates for the other elements and for other mode(s) here -->

XSLT choose template

I have an application written in C# that needs to apply a template name to an xml file that is defined in an XSLT.
Example XML:
<Data>
<Person>
<Name>bob</Name>
<Age>43</Age>
</Person>
<Thing>
<Color>Red</Color>
</Thing>
</Data>
Example XSLT:
<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet version="2.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:fn="http://www.w3.org/2005/xpath-functions">
<xsl:output method="xml" version="1.0" encoding="UTF-8" indent="yes"/>
<xsl:param name="TargetName" />
<xsl:param name="RootPath" />
<xsl:Template Name="AgeGrabber">
<xsl:value-of select="/Person/Age" />
</xsl:Template>
<xsl:Template Name="ColorGrabber">
<xsl:value-of select="/Color" />
</xsl:Template>
</xsl:stylesheet>
Say I wanted to run the template "ColorGrabber" with path "/Data/Thing" and then run another transform with the template "AgeGrabber" with path "/Data". Is this possible? I was thinking I could pass in the path and the template name (hense the 2 params at the top) and then do some type of switch but it looks like xsl:call-template can not take a parameter as the name attribute.
How can I achieve this behaviour?

There are a number of issues with this question:
<xsl:stylesheet version="2.0" ... is specified, however, at present >NET doesn't natively support XSLT 2.0.
Thecode example is not too meaningful, because a single XML document cannot contain both /Person/Age and /Color elements -- a wellformed XML document has only a single top element and it can be either Person or Color, but not both.
In case there was a more meaningful example:
<Person>
<Age>27</Age>
<HairColor>blond</HairColor>
</Person>
one simple solution is:
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output omit-xml-declaration="yes" indent="yes"/>
<xsl:param name="pProperty" select="'Age'"/>
<xsl:template match="/">
<xsl:value-of select="/*/*[name()=$pProperty]"/>
</xsl:template>
</xsl:stylesheet>
and when this transformation is applied on the above XML document, it produces the wanted result:
27
In case the nestedness of the elements of interest can be arbitrary and/or we need to do different processing on the different elements, then an appropriate solution is to use matching templates (not named ones):
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output omit-xml-declaration="yes" indent="yes"/>
<xsl:strip-space elements="*"/>
<xsl:param name="pProperty" select="'HairColor'"/>
<xsl:template match="Age">
<xsl:if test="$pProperty = 'Age'">
This person is <xsl:value-of select="."/> old.
</xsl:if>
</xsl:template>
<xsl:template match="HairColor">
<xsl:if test="$pProperty = 'HairColor'">
This person has <xsl:value-of select="."/> hair.
</xsl:if>
</xsl:template>
</xsl:stylesheet>
When this transformation is applied on the same XML document (above), again the correct result is produced:
This person has blond hair.
Finally, if you really want to simulate higher-order functions (HOF) in XSLT 1.0 or XSLT 2.0, see this answer: https://stackoverflow.com/a/8363249/36305 , or learn about FXSL.

Much simpler: prepare two apply-templates rules (for Age and Color elements) and conditionally send proper node to transform - //Person/Age or //Thing/Color

You got it backwards. You ought to create templates, matching the nodes you want to use.
<xsl:stylesheet>
<xsl:template match="Person|Thing">
<xsl:apply-templates />
</xsl:template>
<xsl:template match="Person">
<xsl:value-of select="Age" />
</xsl:template>
<xsl:template match="Thing">
<xsl:value-of select="Color" />
</xsl:template>
</xsl:stylesheet>

XSLT transform creates StackoverflowException

I tried to perform XSLT transform of a XSD file. My goal is in the end to create SQL from XSD. So far so good, this is what I have:
void Convert()
{
XPathDocument xpathDoc = new XPathDocument(#"myschema.xsd");
string xslPath = #"convert.xsl";
XslCompiledTransform transform = new XslCompiledTransform();
transform.Load(xslPath, new XsltSettings(true, true), null);
using (FileStream fs = File.Create(Path.Combine(System.AppDomain.CurrentDomain.BaseDirectory, "output.sql")))
{
try
{
transform.Transform(xpathDoc, null, fs);
}
catch
{
fs.Close();
}
}
}
This is the XSLT file which is failing:
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
version="1.0"
xmlns:xs="http://www.w3.org/2001/XMLSchema">
<!-- Get schema nodes from this schema and any included schemas -->
<xsl:variable name="contents" select="/|document(//xs:include/#schemaLocation)" />
<xsl:template match="*" >
<xsl:for-each select="$contents" >
<xsl:apply-templates select=".//xs:element" />
</xsl:for-each>
</xsl:template>
<xsl:template match="xs:element">
<xsl:apply-templates />
</xsl:template>
</xsl:stylesheet>
I always get a StackoverflowException in System.Data.SqlXml.dll. How can I stop the recursion? Shouldn't it stop if no xs:element remain?
EDIT:
The original code was from here and it already had the error. I tried to fix it by simplifying the XSLT until only the error remained.

the line
<xsl:apply-templates select=".//xs:element" />
sends the current node (xs:element) to the template it started from. Then it matches it in the for loop and sends itself again. Stack overflow is inevitable.

The problem that causes the endless recursion is here:
<xsl:template match="xs:element">
<xsl:apply-templates />
</xsl:template>
The <xsl:apply-templates> instruction will cause other elements than xs:element to be processed. For all such elements the following template is selected for processing:
<xsl:template match="*" >
<xsl:for-each select="$contents" >
<xsl:apply-templates select=".//xs:element" />
</xsl:for-each>
</xsl:template>
and this closes the loop and causes the endless recursion.
This problem can be avoided in the following way:
<xsl:template match="xs:include">
<xsl:apply-templates select="document(#schemaLocation)/*/>
</xsl:template>
No other special templates are necessary -- just add the templates that process specific xsd elements.

As Woody has answer, you have a circular call ("For every element... apply templates for elements"). So, the proper way is:
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:xs="http://www.w3.org/2001/XMLSchema">
<xsl:template match="/" name="root">
<xsl:param name="schema" select="*/*"/>
<xsl:choose>
<xsl:when test="$schema[self::xs:include]">
<xsl:call-template name="root">
<xsl:with-param name="schema" select="$schema[not(self::xs:include)]|document($schema[self::xs:include]/#schemaLocation)/*/*"/>
</xsl:call-template>
</xsl:when>
<xsl:otherwise>
<xsl:apply-templates select="*/*">
<xsl:with-param name="schema" select="$schema"/>
</xsl:apply-templates>
</xsl:otherwise>
</xsl:choose>
</xsl:template>
</xsl:stylesheet>
With this stylesheet you need to add your templates with param schema been your expanded schema. Also, you need to apply templates with a param schema as select="$schema".
EDIT: Sorry, a little mistake. Also, an explanation: when you process a modular schema you need to get first the complete expanded schema because otherwise you end up calling a recursion template for getting reference and type definitions in diferent schema modules every time. With my template you get the complete expanded schema in $schema param, so when you process a xs:element with #type="someType" you could continue the process with xsl:apply-templates select="$schema[self::xs:complexType[#name='someType']]".

Comparing 2 XML docs and applying the changes to source document

Here's my problem.I have 2 xmlfiles with identical structure, with the second xml containing only few node compared to first.
File1
<root>
<alpha>111</alpha>
<beta>22</beta>
<gamma></gamma>
<delta></delta>
</root>
File2
<root>
<beta>XX</beta>
<delta>XX</delta>
</root>
This's what the result should look like
<root>
<alpha>111</alpha>
<beta>22</beta>
<gamma></gamma>
<delta>XX</delta>
</root>
Basically if the node contents of any node in File1 is blank then it should read the values from File2(if it exists, that is).
I did try my luck with Microsoft XmlDiff API but it didn't work out for me(the patch process didn't apply changes to the source doc). Also I'm a bit worried about the DOM approach that it uses, because of the size of the xml that I'll be dealing with.
Can you please suggest a good way of doing this.
I'm using C# 2

Here is a little bit simpler and more efficient solution that that proposed by Alastair (see my comment to his solution).
This transformation:
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform" >
<xsl:output omit-xml-declaration="yes" indent="yes"/>
<xsl:variable name="vFile2"
select="document('File2.xml')"/>
<xsl:template match="*">
<xsl:copy>
<xsl:copy-of select="#*"/>
<xsl:apply-templates/>
</xsl:copy>
</xsl:template>
<xsl:template match="*[not(text())]">
<xsl:copy>
<xsl:copy-of
select="$vFile2/*/*[name() = name(current())]/text()"/>
</xsl:copy>
</xsl:template>
</xsl:stylesheet>
when applied on this XML document:
<root>
<alpha>111</alpha>
<beta>22</beta>
<gamma></gamma>
<delta></delta>
</root>
produces the wanted result:
<root>
<alpha>111</alpha>
<beta>22</beta>
<gamma></gamma>
<delta>XX</delta>
</root>

In XSLT you can use the document() function to retrieve nodes from File2 if you encounter an empty node in File1. Something like:
<?xml version="1.0" encoding="utf-8"?>
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0">
<xsl:template match="root/*[.='']">
<xsl:variable name="file2node">
<xsl:copy-of select="document('File2.xml')/root/*[name()=name(current())]"/>
</xsl:variable>
<xsl:choose>
<xsl:when test="$file2node != ''">
<xsl:copy-of select="$file2node"/>
</xsl:when>
<xsl:otherwise>
<xsl:copy/>
</xsl:otherwise>
</xsl:choose>
</xsl:template>
<xsl:template match="*">
<xsl:copy>
<xsl:copy-of select="#*"/>
<xsl:apply-templates/>
</xsl:copy>
</xsl:template>
</xsl:stylesheet>

This merge seems very specific.
If that is the case, just write some code to load both xml files and apply the changes as you described.