Application::Exit() throwing errors (Collection was modified; enumeration operation may not execute)

Question

I have a lot of forms (hidden) and i need to close them all with a button, but for some reason it started to throw errors "Collection was modified; enumeration operation may not execute"

"System.InvalidOperationException: Collection was modified; enumeration operation may not execute.  
at System.Collections.ArrayList.ArrayListEnumeratorSimple.MoveNext()
   at System.Windows.Forms.Application.ExitInternal()
   at System.Windows.Forms.Application.Exit(CancelEventArgs e)
   at System.Windows.Forms.Application.Exit()
   ..."

Code

    this->button1->Click += gcnew System::EventHandler(this, &Outro::button1_Click);
...
private: System::Void button1_Click(System::Object^  sender, System::EventArgs^  e) {
                 Application::Exit();
             }

score 0 · Answer 1 · answered May 08 '15 at 18:26

0

That's an error that's telling you that you're accessing a collection from 2 or more threads without lock protection.

Look at the CallStack and see which collection is being accessed.
That error indicates that the ArrayList was changed in a different while being iterated in that thread.

answered May 08 '15 at 18:26

Yochai Timmer

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can it be because of an OnFormClosing method? I deleted it cause i remembered that it worked fine before I implemented it to an other form. – user2921071 May 08 '15 at 18:30
yes, Exit() closes all the forms – Yochai Timmer May 08 '15 at 18:36
It is unclear what is your solution about... – NoWar Sep 12 '16 at 12:56

Application::Exit() throwing errors (Collection was modified; enumeration operation may not execute)

1 Answers1