One thing you will notice if you use my example code for displaying the latest forum posts in a custom UserControl is that announcements and sticky posts are displayed too, and to make it worst, they are sorted by their sticky date (the date a post is set to un-stick) so that they always appear on top.

I haven’t found a really good solution to this problem, so if anyone knows one, please let me know. In the meantime I’ve come up with a routine that filters out all announcements and sticky posts, and goes like this:

int pageSize = 10;

ThreadSet threadSet = Threads.GetThreads(
  -1,
  0,
  pageSize,
  CSContext.Current.User,
  DateTime.MinValue,
  SortThreadsBy.LastPost,
  SortOrder.Descending,
  ThreadStatus.Open,
  ThreadUsersFilter.All,
  false,
  false,
  false,
  false
  );
       
ArrayList forRemoval = new ArrayList();
ArrayList forAddition = new ArrayList();
 
// Loop through the set and filter out announcements and sticky posts
foreach (object o in threadSet.Threads)
{
  Thread t = (Thread) o;
 
  if (t.IsAnnouncement || t.IsSticky)
  {
    forRemoval.Add(o);
 
    // We now need to fetch another thread to substitute
    // the one we just removed         
    while (true)
    {
      ThreadSet newThreads = Threads.GetThreads(
        -1,
        pageSize++,
        1,
        CSContext.Current.User,
        DateTime.MinValue,
        SortThreadsBy.LastPost,
        SortOrder.Descending,
        ThreadStatus.Open,
        ThreadUsersFilter.All,
        false,
        false,
        false,
        false
        );

      if (newThreads.Threads.Count > 0)
      {
        Thread newThread = (Thread) newThreads.Threads[0];
     
        // try again if it's a new announcement or sticky post
        if (!newThread.IsAnnouncement && !newThread.IsSticky)
        {
          forAddition.Add(newThread);
          break;
        }
      }
      else
      {
        break;
      }
    }
  }
}

// Remove unwanted posts
foreach (object o in forRemoval)
  threadSet.Threads.Remove(o);

// Add the substitute posts
threadSet.Threads.AddRange(forAddition);

As you can see this code is neither very aesthetically pleasing to look at, nor very efficient (as opposed to not having to do all this anyway). To counter the overhead created by this I’ve implemented caching of the filtered threads using the mechanisms provided by CommunityServer.

string cacheName = "LatestForumPosts-";
if (CSContext.Current.RolesCacheKey == null)
  cacheName += "Everyone";
else
  cacheName += CSContext.Current.RolesCacheKey;

ThreadSet threadSet;

if ((threadSet = (ThreadSet) CSCache.Get(cacheName)) == null)
{

  /***************************************
   Paste in the first code example here
  ****************************************/

  // Cache the filtered set
  CSCache.Insert(cacheName, threadSet, CSCache.MinuteFactor * 15);
}

This mostly counters the overhead brought on by the filter routine, by refreshing the list only once every 15 minutes for each user group. It works, but it just feels wrong, you now…

One of the things we wanted for WindowsAdvice was for the 10 most recent forum posts to be displayed on the frontpage. CommunityServer doesn’t provide a finished control for this, but does already have the functionality. Here’s a quick post to explain how to find and use this functionality on your own site. I’ve also provided a download to a very basic, but functional UserControl for demonstration.

In the CommunityServer.Discussions assembly, under the CommunityServer.Discussions.Components namespace there is nifty little class named Threads. This class contains a GetThreads method which, when called will return a set of threads that match the criteria’s you supply as parameters.

I won’t go into much detail on the parameters beyond the method signature which I’ve copied out of Reflector:

public static ThreadSet GetThreads(int forumID, int pageIndex, int pageSize, User user, DateTime threadsNewerThan, SortThreadsBy sortBy, SortOrder sortOrder, ThreadStatus threadStatus, ThreadUsersFilter userFilter, bool activeTopics, bool unreadOnly, bool unansweredOnly, bool returnRecordCount);

A few things about the parameters though are worth mentioning.

• For the forumID parameter you can supply -1 instead of a legit ID. This will cause threads from all forums to be returned.
• The user parameter, when supplied with an User object of an actual user (e.g. CSContext.Current.User) will filter the issued query so that only threads which the user actually has access to will be returned.
• ThreadUsersFilter.All will apply no filter, contrary to what it says :)

The GetThreads method returns a ThreadSet object that has a property named Threads on it. This property will return you an ArrayList of Thread objects which you can bind to e.g. a Repeater Control in your UserControl.

Please see the demonstration UserControl for more details on the binding part.

The cool thing about using the GetThreads method (besides the obvious relief of having to dig through the database schema and procedures to return this result yourself) is that you will get full use of the caching and access control mechanisms that CS provides. No worries about performance or security :)

I was thinking about writing a longer article on this topic, so please let me know if that would be interesting, and what specifically you would want to know.