Hi Ken,
I don't exactly know what you wanted to show on your page after the XSLT transformation. Anyways, you would have to take note that the a-tag HREF attribute will NOT process the 'disable-output-escaping="yes|no"'. In your case the following would be the same. In all these cases, including your original post, the hyperlink "My Link" is a valid link that would open/download your [PDF_UDT_Url].
Your original post:
<xsl:param name="EncodedLink">
<xsl:value-of select="udt:PDF_UDT_Url" disable-output-escaping="yes" />
</xsl:param>
<a href="{$EncodedLink}" target="_blank">My Link</a>
Equivalent:
<a href="{$EncodedLink}" target="_blank">My Link</a>
OR
<a>
<xsl:attribute name="href">
<xsl:value-of select="$EncodedLink"/>
</xsl:attribute>
My Link
</a>
OR
<a>
<xsl:attribute name="href">
<xsl:value-of select="$EncodedLink" disable-output-escaping="yes" />
</xsl:attribute>
My Link
</a>
OR
<xsl:element name="a">
<xsl:attribute name="href">
<xsl:value-of select="$EncodedLink"/>
</xsl:attribute>
My Link
</xsl:element>
<xsl:element name="a">
<xsl:attribute name="href">
<xsl:value-of select="$EncodedLink" disable-output-escaping="yes" />
</xsl:attribute>
My Link
</xsl:element>
On your follow-up post, I understand them as they are HTML encoded properly. Try the following and you'll see the difference. Then, compare them by viewing the page source. You can even copy the "/LinkClick.aspx?fileticket=..." and paste it in your browser to test if the links are really valid.
<div><xsl:value-of select="udt:PDF" disable-output-escaping="yes" /></div>
<div><xsl:value-of select="udt:PDF_UDT_Url" disable-output-escaping="yes" /></div>
<div><xsl:value-of select="$EncodedLink" /></div>
<div><xsl:value-of select="$EncodedLink" disable-output-escaping="yes" /></div>
<div><xsl:copy-of select="$EncodedLink" /></div>
If you just wanted to simply force the download to open in new window, you can use tick the 'Enable "Open in new window"' and 'Enforce Download' under List Settings of the the Field Editor. Optional: type in a static text like your "My Link" in the "Link Caption" of the same List Settings.
Finally, a not so beautiful option would be below:
<xsl:text disable-output-escaping="yes"><a href="</xsl:text>
<xsl:value-of select="$EncodedLink" disable-output-escaping="yes" />
<xsl:text disable-output-escaping="yes">" >My Link</a></xsl:text>
Hope this helps and I made sense...
Olan