using document() function in .NET XSLT generates error

<xsl:variable name="res" select="document('')/*/my:resources/("/>

The value of the select attribute is not a syntactically correct XPath expression. Every compliant XSLT processor must raise an error.

Solution:

Correct the above to:

<xsl:variable name="vRes" select="document('')/*/my:resources"/>

If there is still an exception raised, do read about the XsltSettings class.

Then create an instance of XsltSettings with this constructor, like this:

XsltSettings(true, false)

Do not enable scripting -- keep the second argument of the constructor as false.

Below is a more complete code snippet:

// Create the XsltSettings object with document() enabled and script disabled.
XsltSettings settings = new XsltSettings(true,false);

// Create the XslCompiledTransform object and load the style sheet.
XslCompiledTransform xslt = new XslCompiledTransform();
xslt.Load("sort.xsl", settings, new XmlUrlResolver());

Update: Another possible reason for an error is when the XSLT stylesheet is dynamically created in memory (doesn't come from file). In this case an XSLT processor typically cannot resolve the relative uri in document('').

In this last case the solution is to make the wanted element the content of an xsl:variable and to use the xxx:node-set() extension function to address this element.

After tearing my hair out for an entire day and a half, I finally figured out the solution to an identical issue I was seeing.

My code:

NUnit Test:

[Test]
public void Transform_WhenXslUsesTheDocumentFunction_DoesNotThrow()
{
    //Arrange
    string testOutputPath = GetTestOutputPath(
        nameof(Transform_WhenXslUsesTheDocumentFunction_DoesNotThrow)
        );
    string inputXsl = TestFilePaths.GetResource("Import\\DocumentImporter.xsl");
    XsltSettings xsltSettings = new XsltSettings(true, true);
    XmlUrlResolver resolver = new XmlUrlResolver();
    XslCompiledTransform xslCompiledTransform = new XslCompiledTransform();
    xslCompiledTransform.Load(inputXsl, xsltSettings, resolver);

    //Act
    TestDelegate testDelegate = () => xslCompiledTransform.Transform(
        TestFilePaths.MinimumValidXml
        , testOutputPath
        );

    //Assert
    Assert.DoesNotThrow(testDelegate);
}

DocumentImporter.xsl :

<?xml version="1.0" encoding="utf-8"?>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
    xmlns:msxsl="urn:schemas-microsoft-com:xslt" exclude-result-prefixes="msxsl"
>
  <xsl:variable name="DocumentPath" select="'./Document.xml'"/>
  <xsl:variable name="DocumentXML" select="document($DocumentPath)"/>

  <xsl:output method="xml" indent="yes"/>

    <xsl:template match="@* | node()">
      <xsl:value-of select="$DocumentXML//Message"/>
    </xsl:template>
</xsl:stylesheet>

Document.xml :

<?xml version="1.0" encoding="utf-8" ?>
<Message>Document Message</Message>

Eventually I found this:

https://github.com/dotnet/runtime/issues/26969

Informing me that I needed to use a new .Net Core "Feature" which would allow me to use my external xml document, using the snippet:

AppContext.SetSwitch("Switch.System.Xml.AllowDefaultResolver", true);

Final code that works:

[Test]
public void Transform_WhenXslUsesTheDocumentFunction_DoesNotThrow()
{
    AppContext.SetSwitch("Switch.System.Xml.AllowDefaultResolver", true);

    //Arrange
    string testOutputPath = GetTestOutputPath(
        nameof(Transform_WhenXslUsesTheDocumentFunction_DoesNotThrow)
        );
    string inputXsl = TestFilePaths.GetResource("Import\\DocumentImporter.xsl");
    XsltSettings xsltSettings = new XsltSettings(true, true);
    XmlUrlResolver resolver = new XmlUrlResolver();
    XslCompiledTransform xslCompiledTransform = new XslCompiledTransform();
    xslCompiledTransform.Load(inputXsl, xsltSettings, resolver);

    //Act
    TestDelegate testDelegate = () => xslCompiledTransform.Transform(
        TestFilePaths.MinimumValidXml
        , testOutputPath
        );

    //Assert
    Assert.DoesNotThrow(testDelegate);
}