Why do I keep having "Collection was modified; enumeration operation may not execute" in charting in VB.Net

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I was adding random points in my chart.
(Imports System.Windows.Forms.DataVisualization.Charting)
while saving in textfile.
And as data accumulated, I encounter this error:

Exception:Caught: Collection was modified; enumeration operation may not execute. (System.InvalidOperationException)
A System.InvalidOperationException was caught: |Collection was modified; enumeration operation may not execute|
Time: 10/21/2015 10:36:07 AM
Thread:No Name[1456]

I added Try Catch in every code but It does not show any error and graph has red cross in it. What happen?

Posted 20-Oct-15 16:45pm

NekoNao

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Sergey Alexandrovich Kryukov 20-Oct-15 23:40pm

I would like to see how did you manage to handle exception the way it did not handle anything. Too bad you did not demonstrate it. Be careful: not understanding how to handle exceptions can cost you a lot, so better learn it well.
—SA

NekoNao 21-Oct-15 2:00am

it seems like my chart has a problem with background worker.

Sergey Alexandrovich Kryukov 21-Oct-15 2:35am

We could help you only if we had a comprehensive issue description...
—SA

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Ravi Bhavnani · Accepted Answer · 2015-10-20T17:30:00

Solution 1

> What happen?

You attempted to modify a collection while enumerating (iterating) through it. That's not permitted.

/ravi

Posted 20-Oct-15 17:30pm

Ravi Bhavnani

Comments

Sergey Alexandrovich Kryukov 20-Oct-15 23:38pm

Yes, as simple as that, a 5.
The analysis of what can happen if this rule is not enforced could be taken as a home exercise.
—SA

Matt T Heffron 21-Oct-15 13:14pm

+5