The Content Query Ticker Web Part looks like this in operation…

It does require MOSS 2007, and you do need to enable the Publishing Infrastructure on your site collection.

For more details, see this page.

These newsletters belong to different regions, and they have a date on which they should be ‘published’ – or at least, a date at which they’re the most recent item. So, we have two columns to capture that – News Region and Publish Date.

The customer wanted a web part on a page that would show the most recently ‘published’ item for each of those regions. Something like:

I did this with the Content Query Web Part (CQWP) – but how?

Well, first I set my CQWP to query the list of newsletters. They have a specific content type that I queried for. I filtered items with a Publish Date in the future out – although not a secure way of preventing users seeing these items, at least it doesn’t make the obvious.

Next, I set the CQWP to group by News Region, and Sort by descenting Publish Date. So far, so standard – but it would also return multiple items for each region, and display their title, not their region.

This called for a special Itemstyle, which I added using the technique mentioned before for putting ItemStyles into a different file. This made sense; we’re not going to use this style extensively, so it’s best to keep it separate.

Next, I modified my CommonViewFields to bring in the News Region column. I’ve mentioned this before.

Then I wrote my XSL:

Take a look at it – it’s cool.

Looking at the code, you can see I read the News Region that we’re looking at into a variable. I then count up the number of preceding nodes which also have the same value for their News Region.

The first node with a particular News Region value will always be the one with the latest Publish Date that isn’t in the future – therefore, the most recent one for that region. The count statement won’t count nodes for other regions, either. So, if it’s the first, we display it – using the News Region text, rather than the title. Simple!

(But a bugger of an XSL query to figure out)

Personally, I think this is fantastic. Frequently I have been asked to do custom roll-up of content, with customised display. If you have to add to the standard ItemStyles.xsl, then before long your ‘Presentation’ setting for your standard CQWPs is full of highly specific item styles. This way, I can isolate – nearly hide – the existance of my much more specific item styles to general users.

And I’ll say more about what I was doing with it shortly.

It worked – but the links to the announcements themselves didn’t work. The short summary is that is that it appears RSS feeds from Content Query Web Parts don’t work when you query for certain types of list.

What I realised was that there was no server in the URL, so my feed reader’s link to the item was going to a URL starting:

http://_layouts/CopyUtil.aspx?Use=id&Action=dispform ...

I’m now tempted to register the _layouts domain ;p

Anyway, checking in the RSS source showed links to incomplete URLs:

Hmm. So how to fix it? I did some Googling and found references to similar URLs, and the solution seemed to be to modify the ContentQueryMain.xslt file (found in the Style Library > XSL Style Sheets). I couldn’t see why this should make a difference – it’s not to do with the RSS feed – but I thought I’d try just incase I’d misunderstood.

I hadn’t. It didn’t work.

I then wondered if the RSS feed worked for a new Content Query Web Part that had just been added to a page. I added one, and enabled the RSS feed. It did work – the URLs in the links contained the server.

Curious.

I exported both web parts as XML and differenced them. One thing I noticed was that the UseCopyUtil setting was false in the working web part, and true in the one that wasn’t. I changed this to true, imported the web part, and now the URLs had a server at the start. They weren’t valid URLs still, so I swapped back.

Next, I wondered what would happen if I took the web part with the working RSS feed, and slowly changed it over to the query I wanted to run. Presumably, at some point it would break.

It did. When I selected that I wanted to query for Items in an Announcement list rather than a Pages library. I changed my query back to Pages – and the RSS feed worked. I tried changing to query for Document libraries – and the RSS feed worked. Then I tried changing the query to get items from Discussions lists – and the RSS feed failed again.

I then took a look at the page being used for the RSS feed (feed.aspx). All it was really doing was inheriting from the Microsoft.SharePoint.Publishing.Internal.CodeBehind.FeedPage page class. I broke out Reflector, and tried following what was going on inside, but to be honest, it was too complicated, and I couldn’t be bothered.

Either way, it looks like the Content Query Web Part’s RSS feed doesn’t work if you’re querying for Announcement lists.

Here’s an example of one rollup up the ‘Project Documents’ type:

It’s advantages are:

• Can select from an entire Site Collection, a Site and it’s Sub-Sites, or from a List
• Can select by List type
• Can filter the results by Content Type, or Metadata field values
• Can be configured to do Sorting and Grouping
• Can display custom data – but this is a little complex

It’s disadvantages are:

• Customising the view is possible, but tricky.The view has to be defined in XSL, and the Content Query Web part configured correctly to get the data you want to display.
• No pagination of results – it’s just truncated.
• The user can’t select the results order, or add his own filter.
• You can’t query across Site collections.

All in all, I’d say that defining the styles for what you want to display puts this into more a ‘development’ task, which isn’t ideal if you’re trying to push administration out to your users a bit more.

Also, a major issue as far as I’m concerned is the lack of pagination. You can limit the number of items shown, but without an link to the next ‘page’ of items.

Here’s an example of a Content Query Web Part showing some custom data (highlighted in yellow):

In short: Cheap, and available, but has that ‘just a bit awkward’ feel to setting it up, and lacks some of the features you’re likely to want. Often will require someone a bit technical for customisation.

| Introduction | Content Query Web Part | Data View Web Part |

| Lightning Conductor Web Part | Bamboo’s List Roll-Up Web Part | Conclusions |

1. Add extra columns to the selected data (CommonViewFields) by exporting, editing and importing the web. part.
2. Add a new display format to the ItemsStyle.xsl file.

Okay, so I did this, and one of my extra columns of data I wanted to present was shown (‘Project’), but the
other (‘Project Status’) wasn’t. What was going on?

Well, I sort of figured it was the space in the name – SharePoint does a funny encoding of spaces to _x0020_ which is annoying, and often causes errors. Anyway, I opened up SharePoint Manager to check what the field was called internally – and sure enough, it was called Project_x0020_Status. Fair enough, I’d got the internal name right, but using that still didn’t work.

I decided in the end to have a look at what the fields the CQWP was retrieving. But how to? I could define my own XSL, but I didn’t know what use to get the list of fields. Well, I found the answer on Bart Callaerts web site (actually, there is another good ‘how to customise the CQWP article). Anyway, I’m shamelessly plagiarising just in case that page in unavailable.

His idea was to define an Item Style to show all the columns of the retrieved items. The code for this is:

<xsl:template name="ViewFields" match="Row[@Style='ViewFields']" mode="itemstyle">
<xsl:for-each select="@*">
P: <xsl:value-of select="name()" />
</xsl:for-each>
</xsl:template>

And you can download a copy here – copying and pasting from this page can screw up so of the characters.

Anyway, I used this view to see my items:

Looking through that list of fields, I saw that the name of my column (according to the CQWP) is now Project_x005F_x0020_Status. That’s a bit strange, and I don’t know why that’s happened. I guess that Michael Hoffer’s suggestion (don’t use spaces in the names when you create the columns – add them later) is a good one – I reckon it’d have saved me this trouble!

Anyway, this suggestion worked nicely. I’ve highlighted my data in yellow:

The method’s signature is:

Lists.GetListItems( [List], [ViewName], [Query], [ViewFields], [RowLimit], [QueryOptions], [WebID]);

I’m not going to talk about most of these parameters – you can read about them here. For my query, most of these parameters were Null (i.e. they were unused). However, the [List] parameter interested me. It’s the ‘Name’ of the list, though I prefer using a GUID (a unique ID) for the list.

The lookup column I was using was defined in a different site to the one where I was making the GetListItems call. I’d pass the GUID, and get the correct values back. My call actually was:

XmlNode resultNode = _lists.GetListItems( listGuid, null, null, viewFields, null, null, null);

So, this query was finding the correct list elsewhere in the site collection based only on the GUID. Interesting – I’m not passing a WebID, and the list is outside the site I’m currently using the web services of. This set me thinking – clearly the call was selecting by list GUID against a table of all ListItems in the site collection.

I was a little surprised – then it hit me – the Content Query Web Part also does that. But how?

Well, a bit of searching later and I found the SPSiteDataQuery object. The object is used for queries against multiple lists in multiple sites. You can specify the types of list to query, values to filter, order by, display, etc.. I’m pretty sure that this is what the Content Query Web Part uses.

Neat! Now I just need to find a reason to use it!

At the moment, the Content Query Web Part gives you 3 options as to what sites it queries:

1. A specific site
2. This site and its children
3. All sites in the collection

Wouldn’t it be great, though, to form that list of target sites based on a category? For example, in a big company it may have a number of divisions, each with their own ‘Finance’ department. A content query web part that could show content from all the ‘Finance’ category sites across the organisation would be very cool.

Can’t see a way of doing it at the moment though. I suppose I could write my own web-part – but the Content Query Web Part gives you so much already, I don’t want to have to replicate that.