what is the meanning of " += ( s, e )" in the code?
<p>i can't find anywhere what is exactly the <code>+= ( s, e )</code> in the code. </p>

<p>example: </p>

<p><code>this.currentOperation.Completed += ( s, e ) =&gt; this.CurrentOperationChanged();</code></p>

<p>someone can explain ? </p>

<p>Thanks. </p>
