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    <p>Thank you Greg for your answer it happens the way you describe it. However, I am not pleased with this situation because it means that I have to place </p> <pre><code>if(this == nullptr) throw gcnew ArgumentException("this"); </code></pre> <p>at the beginning of every method. Only this would guarantee that my method won't appear at the top of stack-trace as a faulty piece of code without argument validation. </p> <p>I have never come across (this == null) when I was writing in C#. Therefore, I decided to find out how is it different from C++/CLI. I created a sample application in C++/CLI:</p> <pre><code>namespace ThisEqualsNull{ public ref class A { public: void SampleMethod() { System::Diagnostics::Debug::Assert(this != nullptr); } }; public ref class Program{ public: static void Main(array&lt;System::String ^&gt; ^args) { A^ a = nullptr; a-&gt;SampleMethod(); } }; } </code></pre> <p>And a small program in C# that uses the C++/CLI classes with the same Main method:</p> <pre><code>class Program { static void Main(string[] args) { A a = null; a.SampleMethod(); } } </code></pre> <p>Then I disassembled them with Red Gate's .NET Reflector:</p> <pre><code>C++/CLI .method public hidebysig static void Main(string[] args) cil managed { .maxstack 1 .locals ( [0] class ThisEqualsNull.A a) L_0000: ldnull L_0001: stloc.0 L_0002: ldnull L_0003: stloc.0 L_0004: ldloc.0 L_0005: call instance void ThisEqualsNull.A::SampleMethod() L_000a: ret } C# .method private hidebysig static void Main(string[] args) cil managed { .entrypoint .maxstack 1 .locals init ( [0] class [ThisEqualsNull]ThisEqualsNull.A a) L_0000: nop L_0001: ldnull L_0002: stloc.0 L_0003: ldloc.0 L_0004: callvirt instance void [ThisEqualsNull]ThisEqualsNull.A::SampleMethod() L_0009: nop L_000a: ret } </code></pre> <p>The important parts are:</p> <pre><code>C++/CLI L_0005: call instance void ThisEqualsNull.A::SampleMethod() C# L_0004: callvirt instance void [ThisEqualsNull]ThisEqualsNull.A::SampleMethod() </code></pre> <p>Where:</p> <ul> <li>call - Calls the method indicated by the passed method descriptor.</li> <li>callvirt - Calls a late-bound method on an object, pushing the return value onto the evaluation stack.</li> </ul> <p>And now the final conclusion: </p> <h3>C# compiler in VS 2008 treats every method as if it was virtual, thus it it always safe to assume that (this != null). In C++/CLI every method is called as it should so it is necessary to pay attention to the non-virtual method calls.</h3>
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