So what does it do? Well, it’s a feature that comes with MOSS 2007 (unfortunately it isn’t included with WSS 3.0) that enables you to define per-site navigation settings in a declarative way. Until now I always used to write custom API code for this, that I executed from a feature receiver or a custom site provisioning provider.

The Portal Navigation Properties Feature itself is actually very simple. It contains no elements, but is only used to trigger the Microsoft.SharePoint.Publishing.NavigationFeatureHandler feature receiver, which does the real work, based on properties you specify. It is typically used from within a site definition file (ONET.XML), like this:

...

<WebFeatures>

    <Feature ID=”541F5F57-C847-4e16-B59A-B31E90E6F9EA”>

        <!– Portal Navigation Properties Feature –>

        <Properties xmlns=”http://schemas.microsoft.com/sharepoint/”>

            <Property Key=”InheritGlobalNavigation” Value=”True”/>

            <Property Key=”InheritCurrentNavigation” Value=”True”/>

            <Property Key=”IncludeSubSites” Value=”True” />

            <Property Key=”IncludePages” Value=”False” />

            <Property Key=”OrderingMethod” Value=”Automatic”/>

            <Property Key=”AutomaticSortingMathod” Value=”CreatedDate”/>

        </Properties>

    </Feature>

</WebFeatures>

...

Using Reflector I found out the following properties can be used with this feature:

¹ Please note the awful spelling error in “AutomaticSortingMathod”. Ofcourse this should have been “AutomaticSortingMethod”, but apparently someone at Microsoft forgot to run the spell checker over his/her code

Specifying ViewFields involves creating a string of CAML FieldRef elements. For instance if we want our query to return items that contain data for the Title, Created and ID field we use this:

   1: <FieldRef Name=‘Title’/><FieldRef Name=‘Created’/><FieldRef Name=‘ID’/>

As you can see there’s some overhead of boilerplate markup involved. I’ve written a small piece of code that I always use to make my life a little easier. Today I happened to post this code in a reply I wrote on the MSDN forums and also decided to submit it as Community Content to the official SPQuery docs on MSDN. Then I thought I might as well share it with you here. So here it is:

   1: public static string BuildViewFieldsXml(params string[] fieldNames)

   2: {

   3:     const string TEMPLATE = @"<FieldRef Name=’{0:S}’/>";

   4:     StringBuilder sb = new StringBuilder();

   5:     foreach (string fieldName in fieldNames)

   6:     {

   7:         sb.AppendFormat(TEMPLATE, fieldName);

   8:     }

   9:     return sb.ToString();

  10: }

  11:  

  12: // Use it like this:

  13: SPQuery query = new SPQuery();

  14: query.ViewFields = BuildViewFieldsXml("Title", "Created", "ID");

  15:  

  16: // Note that you can specify a variable amount of string parameters, i.e.

  17: query.ViewFields = BuildViewFieldsXml("Title", "Created", "ID", "Author", "Gender");

Yeah, you’re right. This piece of code isn’t exactly rocket science. But you might appreciate it anyway

Last year while working on a MOSS 2007 project for one of our customers I stumbled on what I thought was a bug in SharePoint 2007. I had created a custom list that was filled with Electronic Program Guide (EPG) information for the streaming video media that that site contained. I then created a Webpart that used ASP.Net AJAX to continually show the actual EPG information below the video stream.

In order to obtain the EPG items I used a CAML query to query the EPG list. The list was simply a custom list containing amongst others a column of type DateTime that was called "ProgramEnd". As the name suggests it contained the time the program ended. I then used the following code to create a query that was supposed to obtain the currently broadcasted item and all future items.

   1: const string EPG_QUERY_TEMPLATE = @"

   2: <Where>

   3:  <Geq>

   4:   <FieldRef Name=’ProgramEnd’ />

   5:   <Value Type=’DateTime’>{0}</Value>

   6:  </Geq>

   7: </Where>"; 

   8:  

   9: SPQuery query = new SPQuery();

  10: query.Query = String.Format(EPG_QUERY_TEMPLATE,

  11:     SPUtility.CreateISO8601DateTimeFromSystemDateTime(DateTime.Now)); 

  12: // …

To my surprise this query always returned too many items. Further investigation showed that time part of the query seemed to be ignored completely, so it returned the items as if no time was specified! So instead of getting the current item and all future items it returned all items broadcasted for that day.

After wasting a lot of time debugging, using the U2U Caml Query Builder and looking for an answer / solution on the internet I gave up and wrote a quick hack around it, which fortunately wasn’t very difficult. It would just run the query and run the results through some additional code that checked the ProgramEnd DateTime field and filter out the wrong items, like this:

   1: SPListItemCollection results = …; // The results from the query mentioned above

   2: // Trim the results to only include the current and future items

   3: List<SPListItem> trimmedItems = new List<SPListItem>();

   4: foreach (SPListItem result in results)

   5: {

   6:     DateTime programEnd = (DateTime)result["ProgramEnd"];

   7:     if (programEnd >= DateTime.Now)

   8:         trimmedItems.Add(result);

   9: } 

Fortunately this worked just fine and the customer was happy. I was not…

Today while surfing the Net I stumbled on this entry in the MSDN forums, from which I learned it wasn’t a bug, but that you need to included the "IncludeTimeValue" attribute to the CAML query, like this:

   1: <Where>

   2:  <Eq>

   3:   <FieldRef Name=‘programEnd’ />

   4:   <Value Type=‘DateTime’ IncludeTimeValue=‘TRUE’>

   5:    2008-07-30T12:00:00Z

   6:   </Value>

   7:  </Eq>

   8: </Where> 

If only I had known it was this simple… What bothers me is that this little, but very important attribute seems to be totally undocumented. I couldn’t find any information about it in the WSS / SharePoint SDKs.

Ofcourse once I knew what to look for I found some other blogs and forums mentioning this issue. It turns out the UCSharp blog had already blogged about this way back in October 2007, only a few months after I searched for it. Even Karine Bosch, U2U’s "CAML Girl" and author of the famous U2U CAML Query Builder, says she only recently found out about this. Fortunately she has included support for the "IncludeTimeValue" attribute in her latest version of the U2U Caml Query Builder, which I know a lot of SharePoint developers use to construct and test their CAML queries.

I also noticed that someone called puneetspeed has added some Community Content to the online SharePoint SDK’s SPQuery docs explaining this issue. So hopefully Microsoft will add information about the "IncludeTimeValue" attribute to the official SDK text in the near future.

I’ve uploaded the photos I took to my Flickr account, so check ‘em out. I’ve also uploaded a small video of the “Holland Sport” bicycle race track we had at our booth. Check it out:

It was a very tiring day and I’m going to get some sleep now. I’ll blog about some more about the DevDays later on…

At our booth you’ll be able to compete in a fun bicycle contest and perhaps win one of the six XBOX 360 consoles we are giving away! Hope to see you there. I’m scheduled for booth duty on thursday morning. Yes, that’s during David Platt’s great keynote on “Why Software Sucks”. Fortunately I’ve already seen this one during TechEd Developers 2007 in Barcelona last year and I also own an autographed copy of his book on the topic. But still I’m going to try to sneak away from the booth for a while

As for my SharePoint interests I’m hoping to get a chance to speak with Jan Tielens and Patrick Tisseghem, who are both scheduled to speak at the event. I’ve got some burning questions about Custom Security Trimmers that I hope Patrick can answer.

Oh, and ofcourse I’ll take my digital camera and see if I can take some nice pictures of the event and post them here.

   1: SPList list = GetCommentsList();

   2: const string VIEWFIELDS = "";

   3:  

   4: foreach (string param in params)

   5: {

   6:     // Create fresh new SPQuery instance…

   7:     SPQuery query = new SPQuery();

   8:     query.ViewFields = VIEWFIELDS;

   9:     query.Query = BuildQuery(param);

  10:  

  11:     // And use it…

  12:     SPListItemCollection items = list.GetItems(query);

  13:     ProcessItems(items);

  14: }

As the value of the ViewFields property remained the same for each iteration I decided to create just one SPQuery instance and reuse it, like this:

   1: SPList list = GetCommentsList();

   2: const string VIEWFIELDS = "";

   3:  

   4: // Create just one SPQuery instance…

   5: SPQuery query = new SPQuery();

   6: query.ViewFields = VIEWFIELDS;

   7:  

   8: foreach (string param in params)

   9: {

  10:     // And reuse it…

  11:     query.Query = BuildQuery(param);

  12:     SPListItemCollection items = list.GetItems(query);

  13:     ProcessItems(items);

  14: }

To my surprise this code didn’t work! The first time the SPQuery instance was used it worked just fine. However, during the next iterations of the foreach loop it didn’t seem to get updated.

So, what have we learned today? Never reuse SPQuery instances!

Well… That’s not entirely true. You can reuse SPQuery instances for a very valid reason. If you use the RowLimit property you can limit the number of items returned in the query, which is useful for paging as seen in this sample code (taken from MSDN):

   1: using (SPWeb oWebsiteRoot = SPContext.Current.Site.RootWeb)

   2: {

   3:     SPList oList = oWebsiteRoot.Lists["Announcements"];

   4:     SPQuery oQuery = new SPQuery();

   5:     oQuery.RowLimit = 10;

   6:     int intIndex = 1;

   7:  

   8:     do

   9:     {

  10:         Console.WriteLine("Page: " + intIndex);

  11:         SPListItemCollection collListItems = oList.GetItems(oQuery);

  12:  

  13:         foreach(SPListItem oListItem in collListItems)

  14:         {

  15:             Console.WriteLine(oListItem["Title"]);

  16:         }

  17:         oQuery.ListItemCollectionPosition = 

  18:           collListItems.ListItemCollectionPosition;

  19:         intIndex++;

  20:     } while(oQuery.ListItemCollectionPosition != null);

  21: }

So, only reuse SPQuery instances if you use paging. If you change the actual CAML query you should create a new SPQuery instance for it.

Fortunately getting the beep to shut up forever is relatively simple. Here’s how to do it:

1. Open a Command Prompt window (in Vista make sure you open it using the “Run as administrator” option).
2. Use the following commands:
• To stop the Windows Beep Service:
  net stop beep
• To make sure it never gets started again:
  sc config beep start= disabled

That should take care of them BEEPs

Currently, the training kit contains six hands-on labs, made up of the following technologies:

1. ADO.NET Data Services
2. ADO.NET Entity Framework
3. ASP.NET AJAX History
4. ASP.NET Dynamic Data
5. ASP.NET MVC
6. ASP.NET Silverlight controls

Read more about it on Jonathan Carter’s blog.

You might not know it, but when developing for SharePoint (either WSS 3.0 or MOSS 2007) it is very easy to cause memory leaks, which can ultimately thrash your SharePoint server’s performance. The reason for this is that even though your own code might be written using only managed code, the SharePoint API still uses unmanaged code in some places. These unmanaged resources have to be explicitly disposed of, especially considering the fact they are living inside an ASP.Net web application (SharePoint) and potentially can have a long lifetime.

The problem is that the SharePoint API doesn’t always make clear when exactly you have to dispose of objects explicitly. Sometimes it may look like you’re just inspecting a value of a property, while in the background a whole new object is instantiated, which holds valuable unmanaged resources that should be freed by the caller (you!). Other times you might find yourself disposing an object, only to find out you weren’t supposed to…

Way back in June 2006 Microsoft employees Scott Harris and Mike Ammerlaan released their article Best Practices: Using Disposable Windows SharePoint Services Objects on MSDN, which can be regarded as the mother of all articles on this subject. I think this article is often overlooked and should be considered essential reading material for every serious SharePoint developer out there. Also read their more recent article called Best Practices: Common Coding Issues When Using the SharePoint Object Model, which also handles topics like data and object caching and writing scalable code.

Recently two other Microsoft employees also wrote interesting pieces on this subject. Stefan Goßner did a piece called Dealing with Memory Pressure problems in MOSS/WSS, in which he explains what a "Memory Pressure Situation" is and he lists some common causes and solutions for it. The other interesting read came from Roger Lamb. His entry is called SharePoint 2007 and WSS 3.0 Dispose Patterns by Example and in it he shows some very clear code samples and patterns on how to properly handle SharePoint objects.

Very cool material, guys!

• Added a setup wizard to install the Return of SmartPart.
• Added sample user controls (including connectable user controls and AJAX user controls).
• Added localization support for ASP.NET AJAX user controls.
• Various minor bug fixes.
• Nice 2-minute screencast on how to deploy and test the SmartPart.
• 64 bit version available.

Great work, Jan! I also like the fact you’ve used Lars Fastrup’s SharePoint Solution Installer for deploying SmartPart.