Does changing a item field in a Collection while iterating invalidates the collection?

Question

If do:

foreach(var a in col) {
     a.X = 1;
}

Will my iterator over the collection become invalid?

Thanks

Answer 1

No. You can access the members of the items in the collection. Your code is valid.

What you can't do is modifying the collection itself (by removing or adding items to it) while iterating.

Answer 2

It shouldn't cause a problem. Only if you try to modify the contents of col by doing col.Remove or col.Add would I imagine there would be a problem.