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copied!<p>Firstly, I agree with those that suggest having a finalizer as a backup, but try to avoid it ever being called by explicitly calling myClass.Dispose or through 'using'.</p> <p>e.g.</p> <pre><code>var myClass = new MyClass() try { //do stuff } finally { myClass.Dispose(); } </code></pre> <p>or</p> <pre><code>using (var myClass = new MyClass()) { //do stuff } </code></pre> <p><strong>Marshall.ReleaseComObject</strong></p> <p>If you are using lots of COM objects, I also suggest you use Mashall.ReleaseComObject(comObj) to explicitly clean up references to the RCW.</p> <p>So, the code like this suggested elsewhere:</p> <pre><code>if (comInstance != null) { comInstance.FreeStuff(); comInstance = null; } </code></pre> <p>would become:</p> <pre><code>if (comInstance != null) { comInstance.FreeStuff(); int count = Marshall.ReleaseComObject(comInstance); if (count != 0) { Debug.Assert(false, "comInstance count = " + count); Marshal.FinalReleaseComObject(comInstance); } comInstance = null; } </code></pre> <p>While checking the return value of ReleaseComObject() is not strictly necessary, I like to check it to make sure things are being incremented/decremented as expected.</p> <p><strong>The 2-dot rule</strong></p> <p>If you decide to use this, something to be aware of is that some code may need to be refactored to properly release your COM objects. One in particular is what I call the 2-dot rule. Any line using COM objects that contain 2 dots needs close attention. For example,</p> <pre><code>var name = myComObject.Address.Name; </code></pre> <p>In this statement we get a reference to the Address COM object incrementing its RCW reference count, but we don't have an opportunity to call ReleaseComObject. A better way to do it would be to break it down (try..finally omitted for clarity):</p> <pre><code>var address = myComObject.Address; var name = address.Name; MyReleaseComObject(address); </code></pre> <p>where MyReleaseComObject is a utility method wrapping my count check and FinalReleaseComObject() from above.</p>

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