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    <p>I think that you have a misunderstanding of what <code>dynamic</code> means. Essentially, when you tell the compiler that an object's type is <code>dynamic</code>, you "promise" that the object <strong>at runtime</strong> will support whatever methods or properties that you invoke, in exchange for the compiler not complaining <strong>at compile time</strong>. You also promise that you will face the consequences if you break your promise.</p> <p>When you say that an object is <code>dynamic</code>, the compiler cannot make assumptions about the type, so it uses <code>object</code>, knowing that anything can be stored as <code>object</code>. When you make an <code>IEnumerable&lt;dynamic&gt;</code>, it becomes <code>IEnumerable&lt;object&gt;</code>, with one significant difference: you can call any method on its elements, and the compiler will not say a word:</p> <pre><code>IEnumerable&lt;SomeType&gt; original = ... foreach (dynamic x in original.AsDynamic()) { // Using your method Console.WriteLine(x.SomeUnsupportedMethod()); // The compiler is silent! } </code></pre> <p>Since <code>original.AsDynamic()</code> gives a sequence of <code>dynamic</code> objects, the compiler does not complain about your call to <code>SomeUnsupportedMethod</code>. If the method is indeed not supported at runtime, the program will crash; if the method is actually supported by elements of <code>SomeType</code>, there would be no crash, and the method will be invoked.</p> <p>That's all the <code>dynamic</code> will do for you; statically, the "placeholder" will remain <code>object</code>, and <code>typeof</code> will tell you as much. But the exact capabilities of the object (its methods and properties) will not be examined until runtime.</p>
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    1. POConvert to IEnumerable<dynamic>?
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    1. COAs I understand from discussions in comments to another answer, writing `typeof(IEnumerable<dynamic>)` is actually legal (but not useful!) in C#, but it creates the same runtime type as `typeof(IEnumerable<Object>)`. However, `typeof(dynamic)` is not allowed as a synonym for `typeof(object)`. By the way, `GetType()` will never return an interface type, of course, so the Original Poster was not being precise.
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      1. USJeppe Stig Nielsen
    2. CO@JeppeStigNielsen http://i.stack.imgur.com/9C4sD.jpg
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      1. USRoyi Namir
    3. CO@RoyiNamir I'm not sure I understand your screen shot (I'm not familiar with LINQPad). The two lines have different typography. They are not the output of the two `WriteLine` method calls. The `GetType()` returns a `RuntimeType` object, in the first `WriteLine` the `ToString()` method is called on it. The type will be a generated type (class with a weird name with `<`, `>`, and `__` characters in it) because you have an iterator block (`yield return`). Try this: `if (l.AsDynamic().GetType() == typeof(IEnumerable<Object>)) throw new Exception("Jeppe was wrong!");`
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