Is List thread-safe for reading?

Question

Is the following pseudocode thread-safe ?

IList dataList = SomeNhibernateRepository.GetData();

Parallel.For(..i..)
{
    foreach(var item in dataLi         


        

Answer 1

Yes, List is fine to read from multiple threads concurrently, so long as nothing's writing.

From the documentation:

A List can support multiple readers concurrently, as long as the collection is not modified.

EDIT: Note that your code doesn't necessarily use List - just an IList. Do you know the type returned by GetData()? If you're in control of GetData() you probably want to document that the list returned by it is thread-safe for reading, if it's actually returning a List.