C# Dev for Beginners #20: Thread-Safe Collections - ConcurrentDictionary, BlockingCollection, etc.
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Video Description
List and Dictionary will betray you. Under concurrent access, they corrupt data silently. .NET has better options built specifically for multithreading.
What you'll learn: • Why List and Dictionary fail with threads • System.Collections.Concurrent namespace • ConcurrentDictionary - the thread-safe workhorse • TryAdd, TryGetValue, TryRemove patterns • GetOrAdd - atomic check-and-add • AddOrUpdate - atomic modifications • ConcurrentBag for unordered collections • ConcurrentQueue (FIFO) and ConcurrentStack (LIFO) • BlockingCollection for producer-consumer • The Lazy pattern for expensive factories
Key insights: • Regular collections + threads = silent corruption • Concurrent collections handle locking internally • Try methods never throw on missing keys • GetOrAdd factory might run multiple times • Use Lazy when factory is expensive • BlockingCollection coordinates producers/consumers • CompleteAdding signals no more items coming • Still need locks for multi-operation atomicity
We'll build: • Thread-safe cache with ConcurrentDictionary • GetOrAdd caching pattern • Producer-consumer file processor • Multi-threaded word frequency counter
Previous Video: Introduction to Multithreading Next Video: Tasks - Modern Multithreading ► Full Playlist: https://www.youtube.com/playlist?list=PLGxFXI4dC2shfDgudNdh1FtSLcAZG0-Ba ► Code Repository: https://github.com/benday-inc/csharp-for-beginners-2025
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#CSharp #ThreadSafe #ConcurrentDictionary #DotNet #Programming #Multithreading #CodingTutorial #LearnToCode
0:00 Thread-Safe Collections 1:17 Regular Collections Will Betray You 1:44 List Under Pressure 2:30 The Concurrent Collection Family 3:25 ConcurrentDictionary Basics 4:10 GetOrAdd - The Atomic Pattern 4:32 GetOrAdd - Caching Pattern 4:57 AddOrUpdate - Modify Atomically 5:47 ConcurrentBag - Unordered and Fast 6:33 ConcurrentQueue and ConcurrentStack 6:58 BlockingCollection - Producer/Consumer 7:43 Complete Producer-Consumer Example 8:14 Common Mistakes 9:09 Lazy Factory Pattern 9:29 Choosing the Right Collection 10:23 Q: When Should I Still Use Locks? 11:05 Key Takeaways 12:01 Practice Challenge
Video Info
- Duration: 13:18
- Published: December 15, 2025
