Linking a Multi-Select Lookup Column (XSLT Solution)

The Problem

A common issue in SharePoint 2010 is dealing with linking 2 lists via a look-up column. That’s easy-peasy.

But, what happens when you want to display a view of a record in the main list? By default, you get a semi-colon delimited list of the items from the look-up list, each linked to their record in the look-up list.

Here’s what the standard behavior looks like:

The standard behavior – opening the related item’s display form.

That might be fine in some instances, but what if you want to do something a bit more user-friendly? For example, what if you want to link each look-up item to a page that displays the look-up item’s data and some related data?

Well, you could do that by customizing the standard display page of the look-up table. But, if you do that, you’ll still get the edit ribbon for the look-up item. I’m not a huge fan of the edit ribbon.

I’d rather my users have a more standard web experience. So, I want to link each look-up item to a custom web part page, that pulls in data based on the ID of the item.

The Solution

The best way that I’ve found to do this is to create a custom XSL template, and apply it to the output of your multi-select look-up column in a Data View Web Part. There are a couple of things to understand about how multi-select look-up columns work.

• For each column of this type, there are 2 data fields returned in a DVWP datasource. One of the fields includes the links to the item’s display form. The other field does not.
• The field you want to use with the custom XSL Template below is the one that does not already contain links.
• The field you want will always be the field name with a period (.) appended to the end.
• This field will contain data that looks like so: ID;Title – where the ID is the numeric ID of the item and Title is the actual title of the item. (or whichever field you used for the look-up).

The always helpful Marc Anderson already had a great sample template out there for handling a similar problem. I just took his template 1 step further.

Here’s the code:


<xsl:template name="MultiSelectDisplay">
<xsl:param name="MultiSelectValue"/>
<xsl:param name="MultiSelectDelimiter"/>
<xsl:param name="MultiSelectSeparator"/>
<xsl:param name="Link"/>
<xsl:param name="ThisID" select="0" />
<xsl:choose>
<xsl:when test="contains($MultiSelectValue, $MultiSelectDelimiter)">
<xsl:variable name="before" select="substring-before($MultiSelectValue, $MultiSelectDelimiter)"/>
<xsl:choose>
<!-- if we have a number, pass it back, but don't display anything -->
<xsl:when test= "string(number($before))!='NaN'">
<a>
<xsl:attribute name="href">
<xsl:value-of select="$Link"/><xsl:value-of select="$before"/>
</xsl:attribute>
<xsl:call-template name="MultiSelectDisplay">
<xsl:with-param name="MultiSelectValue" select="substring-after($MultiSelectValue, $MultiSelectDelimiter)"/>
<xsl:with-param name="MultiSelectDelimiter" select="$MultiSelectDelimiter"/>
<xsl:with-param name="MultiSelectSeparator" select="$MultiSelectSeparator"/>
<xsl:with-param name="Link" select="$Link"/>
<xsl:with-param name="ThisID" select="$before"/>
</xsl:call-template>
</a><br/>
</xsl:when>
<!--Otherwise, display and then pass back -->
<xsl:otherwise>
<xsl:value-of select="concat($before, $MultiSelectSeparator)" disable-output-escaping="yes"/>
<xsl:call-template name="MultiSelectDisplay">
<xsl:with-param name="MultiSelectValue" select="substring-after($MultiSelectValue, $MultiSelectDelimiter)"/>
<xsl:with-param name="MultiSelectDelimiter" select="$MultiSelectDelimiter"/>
<xsl:with-param name="MultiSelectSeparator" select="$MultiSelectSeparator"/>
<xsl:with-param name="Link" select="$Link"/>
</xsl:call-template>
</xsl:otherwise>
</xsl:choose>
</xsl:when>
<!-- Display the last item in the list -->
<xsl:otherwise>
<xsl:value-of select="$MultiSelectValue"/>
</xsl:otherwise>
</xsl:choose>
</xsl:template>

Or, in a pretty picture, because WordPress doesn’t do code includes very well:

Image Version of the Template – pretty colors!

To call the code, in your DVWP, include this bit, passing in the relevant parameters:

<xsl:call-template name="MultiSelectDisplay">
<xsl:with-param name="MultiSelectValue" select="@Audience1."/>
<xsl:with-param name="MultiSelectDelimiter" select="';#'"/>
<xsl:with-param name="MultiSelectSeparator" select="'<br />'"/>
<xsl:with-param name="Link">/tools/wnepresources/SitePages/Resources%20by%20Audience.aspx?AudienceID=</xsl:with-param>
</xsl:call-template>


And, again – the pretty picture of the code version:

How to call the XSLT from within your DVWP.

When you include the “MultiSelectDisplay” template in the DVWP’s stylesheet, and call it, you will get output like so:

Finished Solution – 1 item per line, linked to a custom page.

Happy Coding!

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