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    <p>It depends... you specifically say you don't want a generic <em>class</em>... the only other option is a generic <em>method</em> in a <em>non-generic</em> class. The only <em>other</em> time you can get the compiler to emit a <code>constrained</code> call is if you call <code>ToString()</code>, <code>GetHashCode()</code> or <code>Equals()</code> (from <code>object</code>) on a <code>struct</code>, since those are then <code>constrained</code> - if the <code>struct</code> has an <code>override</code> they will be <code>call</code>; if it <em>doesn't</em> have an <code>override</code>, they will be <code>callvirt</code>. Which is why you should always <code>override</code> those 3 for any <code>struct</code> ;p But I digress. A simple example would be a utility class with some static methods - <em>extension</em> methods would be an ideal example, since you also get the advantage that the compiler will switch automatically between the public/implicit API and the extension/explicit API, without you ever needing to change code. For example, the following (which shows both an implicit and explicit implementation) has no boxing, with one <code>call</code> and one <code>constrained</code>+<code>callvirt</code>, which will implemented via <code>call</code> at the JIT:</p> <pre><code>using System; interface IFoo { void Bar(); } struct ExplicitImpl : IFoo { void IFoo.Bar() { Console.WriteLine("ExplicitImpl"); } } struct ImplicitImpl : IFoo { public void Bar() {Console.WriteLine("ImplicitImpl");} } static class FooExtensions { public static void Bar&lt;T&gt;(this T foo) where T : IFoo { foo.Bar(); } } static class Program { static void Main() { var expl = new ExplicitImpl(); expl.Bar(); // via extension method var impl = new ImplicitImpl(); impl.Bar(); // direct } } </code></pre> <p>And here's the key bits of IL:</p> <pre><code>.method private hidebysig static void Main() cil managed { .entrypoint .maxstack 1 .locals init ( [0] valuetype ExplicitImpl expl, [1] valuetype ImplicitImpl impl) L_0000: ldloca.s expl L_0002: initobj ExplicitImpl L_0008: ldloc.0 L_0009: call void FooExtensions::Bar&lt;valuetype ExplicitImpl&gt;(!!0) L_000e: ldloca.s impl L_0010: initobj ImplicitImpl L_0016: ldloca.s impl L_0018: call instance void ImplicitImpl::Bar() L_001d: ret } .method public hidebysig static void Bar&lt;(IFoo) T&gt;(!!T foo) cil managed { .custom instance void [mscorlib]System.Runtime.CompilerServices.ExtensionAttribute::.ctor() .maxstack 8 L_0000: ldarga.s foo L_0002: constrained. !!T L_0008: callvirt instance void IFoo::Bar() L_000d: ret } </code></pre> <p>One downside of an extension method, though, is that it is doing an extra copy of the <code>struct</code> (see the <code>ldloc.0</code>) on the stack, which <em>might</em> be a problem if it is either oversized, or if it is a mutating method (which you should avoid anyway). If that is the case, a <code>ref</code> parameter is helpful, but note that an <em>extension</em> method cannot have a <code>ref this</code> parameter - so you can't do that with an extension method. But consider:</p> <pre><code>Bar(ref expl); Bar(ref impl); </code></pre> <p>with:</p> <pre><code>static void Bar&lt;T&gt;(ref T foo) where T : IFoo { foo.Bar(); } </code></pre> <p>which is:</p> <pre><code>L_001d: ldloca.s expl L_001f: call void Program::Bar&lt;valuetype ExplicitImpl&gt;(!!0&amp;) L_0024: ldloca.s impl L_0026: call void Program::Bar&lt;valuetype ImplicitImpl&gt;(!!0&amp;) </code></pre> <p>with:</p> <pre><code>.method private hidebysig static void Bar&lt;(IFoo) T&gt;(!!T&amp; foo) cil managed { .maxstack 8 L_0000: ldarg.0 L_0001: constrained. !!T L_0007: callvirt instance void IFoo::Bar() L_000c: ret } </code></pre> <p>Still no boxing, but now we also never copy the struct, even for the <em>explicit</em> case.</p>
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    1. POAre there other ways of calling an interface method of a struct without boxing except in generic classes?
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    1. POAre there other ways of calling an interface method of a struct without boxing except in generic classes?
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    1. COperfect!pay my respects!
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