I made some tests to store data from a form to the database more effectively. The CRUD functions and the transactions seem to work fine now. I am still looking for a more effective way to store data from a form to the database, without too much boilerplate code. And it should work with WinForms. Standard data binding with WinForms (bind a control to a data source) has not convinced me yet. I know WPF has better features for data binding, but I want to be independent from WPF (more on this topic another time).
Download NotReallyORM_0.51, try it out, read the comments in source code. And, yes, you can use the framework for ASP.NET, too (it should be thread safe).