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copied!<p>The question boils down to this: the CLI (Common Language Infrastructure) specification says that delegates are reference types. Why is this so?</p> <p>One reason is clearly visible in the .NET Framework today. In the original design, there were two kinds of delegates: normal delegates and "multicast" delegates, which could have more than one target in their invocation list. The <code>MulticastDelegate</code> class inherits from <code>Delegate</code>. Since you can't inherit from a value type, <code>Delegate</code> had to be a reference type.</p> <p>In the end, all actual delegates ended up being multicast delegates, but at that stage in the process, it was too late to merge the two classes. See this <a href="http://blogs.msdn.com/b/brada/archive/2004/02/05/68415.aspx" rel="noreferrer">blog post</a> about this exact topic:</p> <blockquote> <p>We abandoned the distinction between Delegate and MulticastDelegate towards the end of V1. At that time, it would have been a <strong>massive</strong> change to merge the two classes so we didn’t do so. You should pretend that they are merged and that only MulticastDelegate exists.</p> </blockquote> <p>In addition, delegates currently have 4-6 fields, all pointers. 16 bytes is usually considered the upper bound where saving memory still wins out over extra copying. A 64-bit <code>MulticastDelegate</code> takes up 48 bytes. Given this, and the fact that they were using inheritance suggests that a class was the natural choice.</p>

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