In C#, when I attempt to set TileLayoutOrder, I get an Object reference not set to an instance of an object error message.  I do this in either Window_Initialized or MainTiles_Initialized (MainTiles is the name of my xamTilesControl) and I get the error. 

However if I do it in Window_Loaded or MainTiles_Loaded, I don't get the error, but the value never applies.  The only way I can get this to work is by setting in the xaml file, but I want it in C#.

How do I do this?  I am following the documented example, and, nonetheless, I am getting an error.

Thanks,

Mike