Re: [xsl] How to prevent copying non-existing elements?

[Martin Honnen <Martin.Honnen@xxxxxx>]

Ben Stover wrote:
> Lets start with the following simplified piece of XSLT code :
>
> <xsl:template match="/">
>    ....
>   <moxx:someelement>
>       <xsl:value-of select="/moxx:aaa/moxx:bbb"/>
>   </moxx:someelement>
>   ....
>
> So when bbb is an optional element and it does NOT exist in the source XML then the following
> chunk is still created in the target XML doc:
>
> <moxx:someelement></moxx:someelement>
>
> How can I prevent the creation of these frame element tags when there is no source element?
>
> In pseudo code I need something like
>
> <xsl:template match="/">
>    ....
>   "if /moxx:aaa/moxx:bbb exists" then (
>   <moxx:someelement>
>       <xsl:value-of select="/moxx:aaa/moxx:bbb"/>
>   </moxx:someelement>)
>   ....
>
> How can I code this in XSLT ?

If you have

  <xsl:template match="moxx:aaa/moxx:bbb">
    <moxx:someelement>
      <xsl:value-of select="."/>
    </<moxx:someelement>>
  </xsl:template>

and make sure that elements are processed (which for instance the 
built-in templates will do) then you have achieved what you want.

Obviously the verbose way
  <xsl:if test="/moxx:aaa/moxx:bbb">
    <moxx:someelement>
      <xsl:value-of select="/moxx:aaa/moxx:bbb"/>
    </<moxx:someelement>
  </xsl:if>
is also possible.

--

	Martin Honnen
	http://msmvps.com/blogs/martin_honnen/