Provisioning a default layout and content when adding a wiki page

Recently I was challenged with the task to set the layout and content of a wiki page when a new page is added to a team site. As I am used to work with SharePoint publishing, the task sounded easy, but I was wrong.

Text Layout

My first path was to figure out where SharePoint puts the wiki “text layouts”. I discovered this is not how it works. The layouts available for wiki’s are not configurable anywhere.

But using some PowerShell it was easy to get and set the layout as it is the HTML content of the “Wiki Field” column in the list.

$web = Get-SPWeb http://server/teamsite
$list = $web.Lists["Site Pages"]
$listItem = $list.Items[2] # My test page
$listItem["Wiki Content"] # Returns HTML

The HTML content consists of two parts. The layout table and the layout data.

<table id="layoutsTable" style="width: 100%">
    <tbody>
        <tr style="vertical-align: top">
            <td style="width: 100%">
                <div class="ms-rte-layoutszone-outer" style="width: 100%">
                    <div class="ms-rte-layoutszone-inner">
                    </div>
                </div>
            </td>
        </tr>
    </tbody>
</table>
<span id="layoutsData" style="display: none">false,false,1</span>

The layout data describes visibility of the header and footer and the number of columns.

Event receiver

To set the content the first thing in my mind was to add an ItemAdding event receiver, associated with ListTemplateId 119 (WebPageLibrary).

I deployed the solution and added a page and tadah: no content!

Using the debugger to verify my event receiver was triggered, I went to the next option: adding an ItemAdded event receiver. This time I got an exception the page was already modified by another user. Refreshing the page gave me the default content. So, this told me 2 things:

1. It is possible to set default content
2. I forgot to set the Synchronize property

So, after fixing the second thing, I deployed once again and got: no content!

As I used ListItem.Update method in my receiver, I got a version history where it showed the content was set, but the final version still ended up empty.

When faced with utter desperation, working with SharePoint has taught me you always have an escape: launch Reflector.

There I found this gem of code in the SubmitBtn_Click method of the CreateWebPage Class:

SPFile file = SPUtility.CreateNewWikiPage(wikiList, serverRelativeUrl);
SPListItem item = file.Item;
item["WikiField"] = "";
item.UpdateOverwriteVersion();

So, no matter what I do in ItemAdding or ItemAdded, the content always ends up empty!

After this discovery, the fix was removing the code from the ItemAdding and ItemAdded events and moving it to the ItemUpdated event (synchronious) and added a check if the WikiField content is an empty string.

public override void ItemUpdated(SPItemEventProperties properties)
{
    base.ItemUpdated(properties);

    var listItem = properties.ListItem;

    if (!string.IsNullOrEmpty(listItem["WikiField"] as string))
    {
        return;
    }

    this.EventFiringEnabled = false;

    listItem["WikiField"] = html;
    listItem.UpdateOverwriteVersion();

    this.EventFiringEnabled = true;
}

Now every wiki page I add to the team site contains the correct text layout and contains the default HTML.

Related posts:

SharePoint 2010 and Project Server 2010 System Requirements