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POGet Attribute from Dynamically generated Class
 

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    <p>I have run in to a little bit of a problem which is not solved by the generally available solutions to seemingly the same problem.</p> <p>Consider:</p> <p>I have a set of dynamically generated classes, inheriting from a known base Class (lets call it <code>BaseClass</code>). These dynamically generated classes also have dynamically generated <code>Properties</code> with associated attributes.</p> <p>The attributes are also of a custom class, though not dynamically generated:</p> <pre><code>[AttributeUsage(AttributeTargets.Property)] class TypeAttribute: Attribute { private Type _type; public Type Type { get { return _type; } } public TypeAttribute(Type t) { _type = t; } } </code></pre> <p>Then I want to, runtime of course, fetch the value of this assigned attribute:</p> <pre><code>List&lt;PropertyInfo&gt; result = target.GetType() .GetProperties() .Where( p =&gt; p.GetCustomAttributes(typeof(TypeAttribute), true) //.Where(ca =&gt; ((TypeAttribute)ca).) .Any() ) .ToList(); </code></pre> <p>where <code>target</code> is a subclass of <code>BaseClass</code>. The List <code>result</code> is however empty, and this baffles me.</p> <p>I add the attribute using</p> <pre><code>PropertyBuilder propertyBuilder = tb.DefineProperty(propertyName, PropertyAttributes.HasDefault, propertyType, null); ConstructorInfo classCtorInfo = typeof(TypeAttribute). GetConstructor(new Type[] { typeof(Type) }); CustomAttributeBuilder myCABuilder = new CustomAttributeBuilder( classCtorInfo, new object[] { getType(dataType) }); propertyBuilder.SetCustomAttribute(myCABuilder); </code></pre> <p>where <code>dataType</code> is the type to store in the attribute and <code>tb</code> is the <code>TypeBuilder</code> for the class.</p> <p>If I do <code>getCustomAttributes()</code> on the property, I get the expected attributes except the one I'm looking for. But if I do <code>getCustomAttributesData()</code> I get all of them, but the one I'm looking for is of type <code>CustomAttributeData</code> and is not castable to <code>TypeAttribute</code> (if i examine the instance in the VS debugger i can see that the contained information is for a <code>TypeAttribute</code>). I'm guessing that this is a symptom of the problem, but I cannot find the cause - much less the solution.</p> <p>Can anybody point out to me why the <code>result</code> list is empty?</p>
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    1. USfredrik
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    1. COooh, that's fun; that'll take a few minutes for me to set up a test rig for... I'm hoping someone will spot something obvious while I do that!
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      1. USMarc Gravell
 

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