I've made small example how to perform paging, sorting and filtering directly on the data-base sever using LINQ to SQL and RadGridView for WPF.
The data-base is not included however you can use the same code with any data-base with following modifications:
- change the connection string in the app.config file
- change the table name in BindGrid() method:
IQueryable queryable = new DataClasses1DataContext().[Your Table].AsQueryable();
- define desired total number of items per page and total page count
- change the filter expression in the filter button click event handler to desired (currently Contains for Name column)