XSLT extension methods ms:format-date & ms:format-time both output date & time under .NET (6+)

Question

XSLT extension methods ms:format-date & ms:format-time both output date & time under .NET (6+)

David Lowndes 2,640 MVP

I'm porting a .NET FW application to .NET (6 and above).
The application performs an XML to HTML conversion using an XSLT transform via System.Xml.Xsl.XslCompiledTransform.

Under .NET FW, this XSL line:

<xsl:value-of select="ms:format-date('2001-02-03T01:02:03', '')"/>

Produces:

03/02/2001

UK date format since that's my locale.

However, under .NET 6 (I've also tried 8), it produces:

03/02/2001 01:02:03

Similarly, the ms:format-time function also outputs both the date & time.

Is this a known documented change in behaviour (I've been unable to find anything)?

David Lowndes 2,640 Reputation points MVP

2023-10-06T20:54:13.6933333+00:00

Looking at what I presume is the underlying .NET source. On line 169, both "format-date" & "format-time" are handled by the same code, which calls InvokeMsFormatDateTime and doesn't appear to differentiate between outputting just time or just date!
Viorel 122.5K Reputation points

2023-10-07T07:38:22.7766667+00:00

The source code appears to be similar in .NET Framework.

The code seems to differentiate the functions by comparing the name with "format-date".

Did you try to specify the second and third arguments of these functions?
David Lowndes 2,640 Reputation points MVP

2023-10-07T08:53:31.2266667+00:00

Yes, I've tried many things before concluding there's a problem. With the .NET FW version, if you supply a format string with time format characters to format-date, it outputs them literally. Ditto for date characters with format-time, but the .NET version always uses them.

I've found the source to XsltMethods.MSFormatDateTime. The last parameter "isDate" is never used!

Is the .NET FW source publicly available?
David Lowndes 2,640 Reputation points MVP

2023-10-07T13:30:57.5066667+00:00

Thanks for the link to the .NET FW source. I guess the quest for platform portability lost that facility.

I ideally want it to work for the default case with an empty format string, but I might be able to bodge around it as you showed.
David Lowndes 2,640 Reputation points MVP

2023-10-08T19:11:11.2933333+00:00

The workaround (using either 'd' or 'T' rather than the default empty format) works.
I've submitted a bug report on the code in question if you want to follow the outcome, but it's more so that MS are made aware of it - perhaps they'll document it at least!

@Viorel If you convert your comment above to an answer I'll give it a vote.
Thank you.

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David Lowndes 2,640 Reputation points MVP

2023-10-06T20:54:13.6933333+00:00

Looking at what I presume is the underlying .NET source. On line 169, both "format-date" & "format-time" are handled by the same code, which calls InvokeMsFormatDateTime and doesn't appear to differentiate between outputting just time or just date!
Viorel 122.5K Reputation points

2023-10-07T07:38:22.7766667+00:00

The source code appears to be similar in .NET Framework.

The code seems to differentiate the functions by comparing the name with "format-date".

Did you try to specify the second and third arguments of these functions?
David Lowndes 2,640 Reputation points MVP

2023-10-07T08:53:31.2266667+00:00

Yes, I've tried many things before concluding there's a problem. With the .NET FW version, if you supply a format string with time format characters to format-date, it outputs them literally. Ditto for date characters with format-time, but the .NET version always uses them.

I've found the source to XsltMethods.MSFormatDateTime. The last parameter "isDate" is never used!

Is the .NET FW source publicly available?
David Lowndes 2,640 Reputation points MVP

2023-10-07T13:30:57.5066667+00:00

Thanks for the link to the .NET FW source. I guess the quest for platform portability lost that facility.

I ideally want it to work for the default case with an empty format string, but I might be able to bodge around it as you showed.
David Lowndes 2,640 Reputation points MVP

2023-10-08T19:11:11.2933333+00:00

The workaround (using either 'd' or 'T' rather than the default empty format) works.
I've submitted a bug report on the code in question if you want to follow the outcome, but it's more so that MS are made aware of it - perhaps they'll document it at least!

@Viorel If you convert your comment above to an answer I'll give it a vote.
Thank you.

Answer 1

The source of MSFormatDateTime from .NET Framework can be found here:

https://referencesource.microsoft.com/#System.Data.SqlXml/System/Xml/Xsl/Runtime/XsltFunctions.cs,0d7fadce3ae26dee

The workarounds for .NET seem to work:

<xsl:value-of select="ms:format-date('2001-02-03T01:02:03', 'd', 'en-gb')"/>
<xsl:value-of select="ms:format-date('2001-02-03T01:02:03', 'd', 'en-us')"/>

<xsl:value-of select="ms:format-date('2001-02-03T01:02:03', 'D', 'en-gb')"/>
<xsl:value-of select="ms:format-date('2001-02-03T01:02:03', 'D', 'en-us')"/>

<xsl:value-of select="ms:format-time('2001-02-03T01:02:03', 't', 'en-gb')"/>
<xsl:value-of select="ms:format-time('2001-02-03T01:02:03', 't', 'en-us')"/>

<xsl:value-of select="ms:format-time('2001-02-03T01:02:03', 'T', 'en-gb')"/>
<xsl:value-of select="ms:format-time('2001-02-03T01:02:03', 'T', 'en-us')"/>

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XSLT extension methods ms:format-date & ms:format-time both output date & time under .NET (6+)

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