Why won't list view display when <xsl:if> element is used?

Question

I have a list of contacts in SharePoint 2010 that I want to display in 3 different tables based on a TablePos attribute using a custom stylesheet. The TablePos attribute can have a value of Left, Center, or Right. When I don't use the <xsl:if> element, the list view displays all the items in the list view web part. However, when I use the <xsl:if> element to limit the items returned to only those with TablePos='Left', the list view won't render at all. SharePoint doesn't throw an error, it just doesn't render any HTML.

When I use an online XSL Transformation tool, it outputs the html correctly to only show those items that have TablePos='Left' like below, but when I attach the XSL stylesheet to a list view web part, it won't render anything:

<div>
    <div id="tablePos1">
        <table class="it-contacts">
            <tr>
                <td><img src="/test-site/ITMockup/PublishingImages/staff/doe.jpg" alt="John Doe"></td>
                <td>John Doe
                    <br>Chief Information Officer, IT Program Director
                    <br>555-7337
                    <br><a href="mailto:[email protected]">[email protected]</a></td>
            </tr>
        </table>
    </div>
</div>

Here's the pertinent XML:

<dsQueryResponse ViewStyleID="" BaseViewID="1" TemplateType="100" RowLimit="30">
    <Rows>
        <Row ID="1" Title="John Doe" Position="Chief Information Officer, IT Program Director" Duties="Lead IT programs." Phone="555-7337" Email="&lt;a href=&quot;mailto:[email protected]&quot;&gt;[email protected]&lt;/a&gt;" Photo="/test-site/ITMockup/PublishingImages/staff/doe.jpg" TablePos="Left" />
        <Row ID="2" Title="Bobby Sue" Position="Deputy CIO" Duties="Provides overall direction and management for the GIS and Application Development Units" Phone="555-7331" Email="&lt;a href=&quot;mailto:[email protected]&quot;&gt;[email protected]&lt;/a&gt;" Photo="/test-site/ITMockup/PublishingImages/staff/sue.jpg" TablePos="Center" />
        <Row ID="3" Title="Sally Lu" Position="Administrative Resources Manager" Duties="Manages the Word Processing staff" Phone="555-7288" Email="&lt;a href=&quot;mailto:[email protected]&quot;&gt;[email protected]&lt;/a&gt;" Photo="/test-site/ITMockup/PublishingImages/staff/lu.jpg" TablePos="Right" />
    </Rows>
</dsQueryResponse>

And here's the corresponding XSLT:

<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">

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

    <xsl:template match="/">
        <div>
            <div id="tablePos1">
                <table class="it-contacts">
                       <xsl:apply-templates/>
                </table>
            </div>
        </div>
    </xsl:template>

    <xsl:template match="/dsQueryResponse/Rows/Row">
        <xsl:if test="@TablePos = 'Left'">
            <tr>
                <td>
                    <img>
                        <xsl:attribute name="src">
                            <xsl:value-of select="@Photo" />
                        </xsl:attribute>
                        <xsl:attribute name="alt">
                            <xsl:value-of select="@Title" />
                        </xsl:attribute>
                    </img>
                </td>
                <td>
                    <xsl:value-of select="@Title" />
                    <br/>
                    <xsl:value-of select="@Position" />
                    <br/>
                    <xsl:value-of select="@Phone" />
                    <br/>
                    <xsl:value-of select="@Email" disable-output-escaping="yes" />
                </td>
            </tr>
        </xsl:if>
  </xsl:template>

</xsl:stylesheet>

Any ideas why this isn't rendering in the list view web part?

Answer 1

After taking some time away from it, I figured out what was going on. When I initially added the list view web part, the TablePos column had not yet been created in the list, and wasn't included in the view of the web part. I was generating the XML using a second list view web part that included the TablePos column by default, so it was returning XML for that column. When I modified the view of the first web part to include the new TablePos column and added the custom XSLT, the list returned only those items that had TablePos='Left'.