Question

I’m looping through a List of elements with foreach, like this:

foreach (Type name in aList) {
   name.doSomething();
}

However, in an another thread I am calling something like

aList.Remove(Element);

During runtime, this causes an InvalidOperationException: Collection was modified; enumeration operation may not execute. What is the best way to handle this (I would perfer it to be rather simple even at the cost of performance)?

Thanks!

Answer 1

Thread A:

lock (aList) {
  foreach (Type name in aList) {
     name.doSomething();
  }
}

Thread B:

lock (aList) {
  aList.Remove(Element);
}

This ofcourse is really bad for performance.