How to avoid a synchronizationlockexception?

I`ve got this error in Monitor.Exit(resource); This error always appears if i use Monitor.TryEnter(resource) and then exit it after several methods.I wanted to use it with "ref bool" as a lock but it doesn't work.

Monitor.TryEnter(fork[second]);
if (Monitor.TryEnter(fork[second])&&fork[second].IsUsing == false)
{
  fork[second].IsUsing = true;
  del.Invoke(String.Format("Ph {0} took  {1} ", philosopherName, second + 1));

  PauseCheck(rd.Next(60, 100));
  Monitor.TryEnter(fork[number]);
  if (Monitor.TryEnter(fork[number])&&fork[number].IsUsing == false)
  {
    entermon1 = true;
    Monitor.Exit(fork[second]);
    fork[number].IsUsing = true;
    Monitor.Exit(fork[number]);
    checkph = true; DonotNeed = true;
  }

  if (entermon1 == false)
  {
    Monit开发者_Python百科or.Exit(fork[second]);
  }
  entermon1 = false;                            
}

You can't lock on value types - only on objects, and you definitely don't want to lock on a boxed value unless you're maintaining a reference to that box.

My guess is that you're calling Monitor.Exit after Monitor.TryEnter returned false due to another thread owning the lock - you should only exit the lock if you already own it.