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POCan a struct property be retrieved by its string name in Objective-C?
 

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  1. POCan a struct property be retrieved by its string name in Objective-C?
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    <p>I have an object which has a property which is a struct like the following:</p> <pre><code>struct someStruct{ float32 x, y; }; </code></pre> <p>And what I'd like to do is invoke the getter for that struct property via a string:</p> <pre><code>id returnValue = [theObject performSelector:NSSelectorFromString(@"thePropertyName")]; </code></pre> <p>But as you can see "performSelector:" returns an object, not a struct. I've tried every way of casting I could think of, to no avail, which makes me think I'm missing something - perhaps something easy... </p> <p>Any ideas how returnValue can be coaxed back into a struct? Thanks!</p> <p>Edit: Whoever the original responder was (he's since deleted his post for some reason) - you were right: The following, based on your answer, works:</p> <pre><code>StructType s = ((StructType(*)(id, SEL, NSString*))objc_msgSend_stret)(theObject, NSSelectorFromString(@"thePropertyName"), nil); </code></pre> <p>Edit 2: A fairly detailed look at the issue can be found <a href="http://www.sealiesoftware.com/blog/archive/2008/10/30/objc_explain_objc_msgSend_stret.html" rel="nofollow">here</a>.</p> <p>Edit 3: For symmetry's sake, here's how to set a struct property by its string name (note that this is exactly how the accepted answer accomplishes setting, whereas my problem required the slightly different approach for the getter mentioned in the first edit above):</p> <pre><code>NSValue* thisVal = [NSValue valueWithBytes: &amp;thisStruct objCType: @encode(struct StructType)]; [theObject setValue:thisVal forKey:@"thePropertyName"]; </code></pre>
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