Question

In a c# threading app, if I were to lock an object, let us say a queue, and if an exception occurs, will the object stay locked? Here is the pseudo-code:

int ii; lock(MyQueue) {    MyClass LclClass = (MyClass)MyQueue.Dequeue();    try    {       ii = int.parse(LclClass.SomeString);    }    catch    {      MessageBox.Show('Error parsing string');    } } 

As I understand it, code after the catch doesn’t execute – but I have been wondering if the lock will be freed.

Answer 1

First; have you considered TryParse?

in li; if(int.TryParse(LclClass.SomeString, out li)) {     // li is now assigned } else {     // input string is dodgy } 

The lock will be released for 2 reasons; first, lock is essentially:

Monitor.Enter(lockObj); try {   // ... } finally {     Monitor.Exit(lockObj); } 

Second; you catch and don’t re-throw the inner exception, so the lock never actually sees an exception. Of course, you are holding the lock for the duration of a MessageBox, which might be a problem.

So it will be released in all but the most fatal catastrophic unrecoverable exceptions.