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    <h2>Update</h2> <p>Thinking about your problem a bit more generally, I think what you're actually trying to accomplish here is achievable in a much simpler way, without using a <code>System.Threading.Timer</code> at all.</p> <p>Is this basically what you want your method to do? Perform <code>action</code> after a specified number of milliseconds? If so, I would suggest something like the following alternative implementation instead:</p> <pre><code>private void Delay(Action action, int ms) { if (ms &lt;= 0) { action(); return; } System.Threading.WaitCallback delayed = state =&gt; { System.Threading.Thread.Sleep(ms); action(); }; System.Threading.ThreadPool.QueueUserWorkItem(delayed); } </code></pre> <p>...by the way, are you aware that in the code you posted, specifying a non-zero value for <code>ms</code> will cause <code>action</code> to be executed twice?</p> <hr> <h2>Original Answer</h2> <p>The <code>timerstate</code> class really isn't necessary. Just add a <code>System.Threading.Timer</code> member to whatever class contains your <code>Delay</code> method; then your code should look like this:</p> <pre><code>public class Delayer { private System.Threading.Timer _timer; private void Delay(Action action, Int32 ms) { if (ms &lt;= 0) { action(); } _timer = new System.Threading.Timer( (o) =&gt; action(), null, ms, System.Threading.Timeout.Infinite); } } </code></pre> <p>Now, I see that you are specifying the <code>period</code> argument of the timer's constructor as <code>System.Threading.Timeout.Infinite</code> (-1). What this means is that you intend for your timer to call <code>action</code> <strong>once</strong>, after <code>ms</code> has elapsed; am I right? If this is the case, then there's actually not much need to worry about the timer being disposed anyway (i.e., it will be, and that's fine), assuming a relatively low value for <code>ms</code>.</p> <p>Anyway, if you're going to hold onto an instance of an <code>IDisposable</code> object (like <code>System.Threading.Timer</code>), you should generally dispose of that member when <em>your</em> object (i.e., this instance) is disposed of. I believe <code>System.Threading.Timer</code> has a finalizer that will cause it to be disposed of eventually anyway, but it's best to dispose of things as soon as you don't need them anymore. So:</p> <pre><code>public class Delayer : IDisposable { // same code as above, plus... public void Dispose() { _timer.Dispose(); } } </code></pre>
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    1. POSystem.Threading.Timer keep reference to it
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    1. USDan Tao
    1. USDan Tao
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    1. COYeah I was trying to avoid keeping a reference to the timer explicitly. The application reads a configuration of "Actions" from xml, Delay being a type of "Action". I don't want to have to root the "delayer" - but I'll have a bit more of a think about it. Thanks.
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      1. USDaniel James Bryars
    2. CO@Daniel: Well, I didn't mean to suggest that you should write a new class called `Delayer`, but rather that whatever class *of which your `Delay` method is already a member* needs to hold on to the reference. That said, have you taken a look at my suggested alternative? I think it would exhibit the behavior you want without having to deal with the mess of maintaining and disposing of a timer.
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      1. USDan Tao
    3. COUnforunately, using the Queue is not a guaranteed way to handle this because if the queue is full or delayed, then your delay is {the queue delay}+{your delay} which may or may not matter to you.
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      1. USJerry Nixon - MSFT
 

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