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POCompare objects and determine common type
 

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    <p>Short Version: Are the comments in the code correct? I think they are incorrect and should be reversed.</p> <pre><code>public Type GetTestClass(Object left, Object right) { if (left == null || right == null) return null; Type leftClass = left.GetType(); Type rightClass = right.GetType(); Type testClass; if (leftClass.IsInstanceOfType(right)) { testClass = leftClass; if (!rightClass.IsInstanceOfType(left)) { // rightClass is a subclass of leftClass testClass = rightClass; } } else if (rightClass.IsInstanceOfType(left)) { testClass = rightClass; if (!leftClass.IsInstanceOfType(right)) { // leftClass is a subclass of rightClass testClass = leftClass; } } else { // The two classes are not related. testClass = null; } return testClass; } </code></pre> <p>I came across this code in a code-base that I am working on and I think the comments are incorrect. I believe that the comments <code>//rightClass is a subclass of leftClass</code> and <code>//leftClass is a subclass of rightClass</code> are incorrect. For example, if <code>leftClass</code> is of type <code>Object</code> and <code>rightClass</code> is of type <code>MyClass</code> (which inherits from Object) then this is the how I believe the code works...</p> <ol> <li><code>Object</code> is an instance of <code>MyClass</code> is FALSE</li> <li><code>MyClass</code> is an instance of <code>Object</code> is TRUE</li> <li><code>testClass</code> is set to <code>MyClass</code></li> <li>NOT (<code>Object</code> is an instance of <code>MyClass</code> is FALSE) is TRUE</li> <li><code>testClass</code> is set to <code>Object</code></li> <li><code>testClass</code> is returned which == <code>Object</code></li> </ol> <p>I believe this is the correct functionality... ultimately the code is attempting to return the super-most class (you could also say the common Base class) of the two classes, or null if they are not related. Using the example above (steps 1-5) isn't it actually correct to say that the leftClass is a SUPER class of rightClass... or, reversed, the rightClass is a SUBCLASS of leftClass?</p>
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    1. COPlease tell me you are going to slap an [Obsolete("DO NOT USE")] on that!
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    2. COI've added code that I had left out. There is more going on in the code than what I've put up here... but it doesn't apply to my question. I really do appreciate the comments & code below so far... but I think my question hasn't been answered yet which is: Is my understanding of the code correct and the comments are incorrect?
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    3. CO@Steve, `leftClass.IsInstanceOfType(right)` means that "the right is a left". `rightClass.IsInstanceOfType(left)` means that "the left is a right". If the right is a left, but the left is not a right, then the left must be the super class, and the right must be the subclass. This is equivalent to the first case, where you have the comment "rightClass is a subclass of leftClass".
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      1. USsmartcaveman
 

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