How would you simply Monitor.TryEnter

Question

I'm trying to make things simpler. Here is my code:

    If Threading.Monitor.TryEnter(syncRoot) Then
        Try
            'do something
        Finally
            Threading.Monitor.Exit(syncRoot)
        End Try
    Else
        'do something else
    End If

This is even worse than the ReaderWriterLock in terms of noise. I can use C# or VB, so answers applying to either will be welcome.

score 6 · Accepted Answer · answered Oct 04 '08 at 10:31

6

Use a delegate?

E.g.

public bool TryEnter(object lockObject, Action work) 
{
    if (Monitor.TryEnter(lockObject)) 
    {
       try 
       {
          work();
       }
       finally 
       {
           Monitor.Exit(lockObject);
       }        
       return true;
     }

     return false;
}

answered Oct 04 '08 at 10:31

Richard Nienaber

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Totally useless for VB (no anonymous Action delegates), but I can see it working with C#. Can you show how you foresee it being called? – Jonathan Allen Oct 04 '08 at 11:14
Simplest would be with a lambda: TryEnter(obj, ()=>{...code...})), where the return tells you whether it was done or not. – Marc Gravell Oct 04 '08 at 11:56
1

Now that VB 10 has anonymous delegates, this is my favorite solution. – Jonathan Allen May 19 '10 at 05:26

score 4 · Answer 2 · edited May 23 '17 at 12:33

4

This is very similar to your last post, and I would expect a similar answer. The only significant difference is that you might return "null" from your method if the timeout fails - then the "Dispose()" is not called, and you can easily check the value:

using(var token = GetLock(syncLock, timeout)) {
  if(token != null) { ... }
}

The only real glitch is that you don't necessarily want to add an extension method to "object" (or even "T where T : class")...

Jon Skeet has looked at this in the past - worth a look.

edited May 23 '17 at 12:33

Community

1
1

answered Oct 04 '08 at 09:37

Marc Gravell

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Passing a possible null to the using block is a neat trick. But it still feels kludgey to me. – Jonathan Allen Oct 04 '08 at 09:50

How would you simply Monitor.TryEnter

2 Answers2