Bilal Haidar explains the Silverlight error "The remote server returned an error: NotFound."
While working on a Silverlight application and you face such exception: "The remote server returned an error: NotFound." You should check this blog post: Silverlight and WCF Essentials - Fiddler.
Bilal Haidar is talking about columns and rows for DataGrid.
There is a need in every database-driven application to display data to end-users in the form of rows and columns that mimic the Excel sheets with which most end-users are familiar. Fortunately for us, Silverlight provides a rich and robust DataGrid control.