WPF Datagrid Lazy load
Loading data: 200k rows is a lot of data that no one (user) wants to see in one place. It will definitely reduce your UI user experience. So your best bet is to filter your data just to reduce the amount of it (for example do not show closed orders, just show the open ones). If you can't do so, you should use Virtualization. I didn't see any applications that use pagination in order to show data (Of course except in web). Most of the time it isn't such a good approach. But if you are talking about a type of data that is like search engines results you must use it. But keep in mind that most users won't exceed page 10 in search engines results.
Filtering: I would suggest doing it on your server side for such a huge amount of data (SQL Server here), or as I said first filter the whole 200k to reduce the amount on server side and then filter it (for user) in order to find something, on the client side. You might also find the following link helpful:
- http://www.codeproject.com/KB/WPF/DataGridFilterLibrary.aspx
Sorting: Again I would suggest server-client solution but you might also find following links helpful:
- http://blogs.msdn.com/b/jgoldb/archive/2008/08/26/improving-microsoft-datagrid-ctp-sorting-performance.aspx
- http://blogs.msdn.com/b/jgoldb/archive/2008/08/28/improving-microsoft-datagrid-ctp-sorting-performance-part-2.aspx
- http://blogs.msdn.com/b/jgoldb/archive/2008/10/30/improving-microsoft-datagrid-sorting-performance-part-3.aspx
Many people don't use default SortMemberPath of WPF datagrid just because it uses reflection on every single record and this will highly reduce the performance of the sorting process.
Hosein