Prism for Silverlight: How to maintain views in a specific order inside a region

Question

I am creating sort of a \"Navigation panel\" (which is actually an ItemControl) for SL and using Regions to allow each module to add his link to the panel.

Problem i

Answer 1

At least in prism V4 there you can tell the region manager how to sort the views in a specific region. You just need to provide a compare function to the region.

This example sorts by a very stupid value, the function name:

private static int CompareViews(object x, object y)
{
  return String.Compare(x.ToString(), y.ToString());
}

this._regionManager.Regions["MyRegion"].SortComparison = CompareViews;

Of course the region needs to be known to the region manager before you can set the SortComparison. So far the only workaround I found to achieve this was to defer to set the comparison function using the Dispatcher:

private readonly IRegionManager _regionManager;

[ImportingConstructor]
public ShellViewModel(IRegionManager regionManager)
{
  this._regionManager = regionManager;
  Dispatcher dp = Dispatcher.CurrentDispatcher;
  dp.BeginInvoke(DispatcherPriority.ApplicationIdle, new ThreadStart(delegate
  {
    if (this._regionManager.Regions.ContainsRegionWithName("MyRegion"))
      this._regionManager.Regions["MyRegion"].SortComparison = CompareViews;
  }));
}

Of course you should use some more useful information than the class name for the sorting order, but this should be easy to solve.