30 lines
903 B
Markdown
30 lines
903 B
Markdown
## List<T>.ForEach can throw exception when modifying list item
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### Scope
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Edge
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### Version Introduced
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4.5
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### Source Analyzer Status
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Available
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### Change Description
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Beginning in .NET 4.5, a `List<T>.ForEach` enumerator will throw an InvalidOperationException exception if an element in the calling collection is modified. Previously, this would not throw an exception but could lead to race conditions.
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- [x] Quirked
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- [ ] Build-time break
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### Recommended Action
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Ideally, code should be fixed to not modify lists while enumerating their elements because that is never a safe operation. To revert to the previous behavior, though, an app may target .NET 4.0.
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### Affected APIs
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* ``M:System.Collections.Generic.List`1.ForEach(System.Action{`0})``
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### Category
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Core
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[More information](https://msdn.microsoft.com/en-us/library/hh367887\(v=vs.110\).aspx#core)
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<!-- breaking change id: 5 -->
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