SqlBulkCopy from a List<>

Question

How can I make a big insertion with SqlBulkCopy from a List<> of simple object ?

Do I implement my custom IDataReader ?

Answer 1

Depending on what you are trying to accomplish by calling SqlBulkCopy in the first place, it might make more sense to use a Table-Valued Parameter (TVP). Using a TVP would make it trivial to send in a collection of any custom type. The data can be streamed in so you can avoid the DataTable (much like in @Marc Gravell's answer) and you can avoid SqlBulkCopy as well. TVP's allow for completely flexibility of how to handle the data once it gets to SQL Server as you call a Stored Procedure to pass the TVP data into and it appears as a Table Variable that you can do anything with, not just INSERT (which is the case with SqlBulkCopy). You can also get data back via a SqlDataReader, data such as newly created IDENTITY values. I added an example and some additional notes on this answer: How can I insert 10 million records in the shortest time possible?. And several years ago I wrote an article on SQL Server Central (free registration required), Streaming Data Into SQL Server 2008 From an Application, which is also noted in that linked answer, providing a working example of passing in a Generic List of a custom type, streamed in from a 3 million row text file.