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POC#: Initializing an event handler with a dummy
 

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    <p>I've seen this sort of code some places:</p> <pre><code>public event SomeEventHandler SomeEvent = (s, e) =&gt; { }; </code></pre> <p>Is that a recommended way of doing things? What does it solve, and does it have any noteworthy side effects? Will I still have to do null checks? Or is that exactly what I don't have to do any more? Will garbage collection still work as it should?</p> <hr> <p>For example:</p> <pre><code>private PropertyChangedEventHandler propertyChanged; private readonly object propertyChangedLock = new object(); public event PropertyChangedEventHandler PropertyChanged { add { lock (propertyChangedLock) propertyChanged += value; } remove { lock (propertyChanged) propertyChanged -= value; } } protected void OnPropertyChanged(string propertyName) { PropertyChangedEventHandler handler; lock (propertyChangedLock) handler = propertyChanged; if (handler != null) handler(this, new PropertyChangedEventArgs(propertyName)); } </code></pre> <p>Could I change the first line into this:</p> <pre><code>private PropertyChangedEventHandler propertyChanged = (s, e) =&gt; { }; </code></pre> <p>And then skip the null-check in the OnPropertyChanged method? And if I then skip the null-check could I then also skip the lock? If so that would give me this:</p> <pre><code>protected void OnPropertyChanged(string propertyName) { propertyChanged(this, new PropertyChangedEventArgs(propertyName)); } </code></pre> <p>Would that be safe when taking the initialization into account? Or are there some side effects I have missed?</p>
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    1. COMy article on the subject: http://blogs.msdn.com/ericlippert/archive/2009/04/29/events-and-races.aspx
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    2. CONice article! In other words, removing the null check would be thread-safe in this case. But subscribers needs to have smart handlers that doesn't break. Did I get that right?
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