Sending Dataset from WCF to silverlight Appliaction

I want to bind the data to datagrid in silverlight my wcf method is retriving the data from database.
but the issue is we cant used datatable or dataset in silverlight. so i m trying to convert it in some type of collection.
For that i have created class and the properties and the object of class i am adding into the the list collection. but here the scenario is different the return columns are not fixed they are decide at runtime means which columns and how many are return columns are not fixed.
So i am serching for the solution to convert dataset into the compatible collection to the silverlight.