May 10, 2019 06:28 AM|Jenifer Jiang|LINK
Collection was modified; enumeration operation may not execute.
In general,.Net collections do not support being enumerated and modified at the same time.
So when you're iterating on a collection, you cannot modify its elements, add new ones or delete any elements.
To fix the issue, you could copy collection to another.
foreach (System.Collections.DictionaryEntry entry in e.Values.ToArray())
For more about the error, you could refer to: