Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Welcome To Ask or Share your Answers For Others

Categories

0 votes
486 views
in Technique[技术] by (71.8m points)

c# - is locking necessary for Dictionary lookup?

lock(dictionaryX)
{
   dictionaryX.TryGetValue(key, out value);
}

is locking necessary while doing lookups to a Dictionary ?

THe program is multithreaded, and while adding key/value to dict. dict is being locked.

See Question&Answers more detail:os

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome To Ask or Share your Answers For Others

1 Reply

0 votes
by (71.8m points)

As mentioned here:

Using TryGetValue() without locking is not safe. The dictionary is temporarily in a state that makes it unsuitable for reading while another thread is writing the dictionary. A dictionary will reorganize itself from time to time as the number of entries it contains grows. When you read at the exact time this re-organization takes place, you'll run the risk of finding the wrong value for the key when the buckets got updated but not yet the value entries.

UPDATE: take a look at "Thread Safety" part of this page too.


与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
OGeek|极客中国-欢迎来到极客的世界,一个免费开放的程序员编程交流平台!开放,进步,分享!让技术改变生活,让极客改变未来! Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Click Here to Ask a Question

...