Is there a limit of elements that could be stored in a List?

Question

Is there a limit of elements that could be stored in a List ? or you can just keeping adding elements untill you are out of memory ?

Option

Answer 1

The current implementation of List<T> uses Int32 everywhere - to construct its backing array, for its Count property, as an indexer and for all its internal operations - so there's a current theoretical maximum of Int32.MaxValue items (2^31-1 or 2147483647).

But the .NET framework also has a maximum object size limit of 2GB, so you'll only get anywhere near the items limit with lists of single-byte items such as List<byte> or List<bool>.

In practice you'll probably run out of contiguous memory before you hit either of those limits.

Clubfoot

Theoretically that means you can only randomly access items up to Int32.MaxValue, not how many elements can there be, theoretically, of course. – Krone

@Martinho: Well, the current implementation uses Int32 everywhere, so it's not just random access that's restricted to 2^31 items. (Of course, the use of Int32 internally is just an implementation detail, but properties like the indexer and Count are part of the public contract.) – Clubfoot