Error loading SL app that uses SL class library

Feb 21, 2009 at 9:30 PM
Edited Feb 21, 2009 at 9:34 PM
I have a Silverlight application that loads a composite SL control from a Silverlight class library.  I have followed all of the Blueprint steps for installing and loading this part in Sharepoint, and can successfully add and configure the Sharepoint webpart.  When the Sharepoint webpart loads, I can see the initial Silverlight loading animation, but my SL control never displays.  IE displays "Error on page" then "Done" with the error icon in the lower left corner.  When I open the IE error window, the details of the error message show the error as

"Unhandled error in Silverlight 2 Application Unknown attribute HorizontalAlignment on element RadarGrid....."

Here is my Page.xaml:

<UserControl x:Class="AITSilverlight.App.Page"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Width="800" Height="600"
    xmlns:AITSilverlight_Library="clr-namespace:AITSilverlight.Library;assembly=AITSilverlight.Library">
    <Grid x:Name="LayoutRoot" Background="White">

        <AITSilverlight_Library:RadarGrid
            HorizontalAlignment="Left"
            VerticalAlignment="Top"
            x:Name="xRadarGrid">
        </AITSilverlight_Library:RadarGrid>
    </Grid>
</UserControl>

As you can see, this is a very basic xaml file, with the main difference from the Blueprint samples being the xmlns: namespace for my SL library (AITSilverlight.Library).  Also, my library uses SL controls from ComponentOne, which are additional library dlls.  I have verified that my xap file does include all of the required dlls.

I suspect that Sharepoint does not have any "knowledge" of my SL library dll, so the xmlns: namespace does not resolve to a known dll. 

Is this Silverlight scenario of using SL control library dlls that are separate from the main application dll capable of being hosted in a Sharepoint webpart?  I know I can always "cheat" and use a Sharepoint web viewer to a working website. But, I am working on several Silverlight "proof-of-concept" projects for a client that prefers to have these SL controls shown as "native" Sharepoint parts.

Any help with this would be greatly appreciated.

TIA,
Elaine