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POUsing reflection to specify the type of a delegate (to attach to an event)?
 

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  1. POUsing reflection to specify the type of a delegate (to attach to an event)?
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    <p>What I effectively want to do is something like this (I realise this is not valid code):</p> <pre><code>// Attach the event. try { EventInfo e = mappings[name]; (e.EventHandlerType) handler = (sender, raw) =&gt; { AutoWrapEventArgs args = raw as AutoWrapEventArgs; func.Call(this, args.GetParameters()); }; e.AddEventHandler(this, handler); } ... </code></pre> <p>Now I know that the e.EventHandlerType will always <strong>derive</strong> from EventHandler&lt;AutoWrapEventArgs&gt;. However, I can't just do:</p> <pre><code> EventHandler&lt;AutoWrapEventArgs&gt; handler = (sender, raw) =&gt; { AutoWrapEventArgs args = raw as AutoWrapEventArgs; func.Call(this, args.GetParameters()); }; e.AddEventHandler(this, handler); </code></pre> <p>As .NET complains that there is no conversion applicable from EventHandler&lt;AutoWrapEventArgs&gt; to EventHandler&lt;DataEventArgs&gt; when AddEventHandler is called. This is the exact message:</p> <pre><code>Object of type 'System.EventHandler`1[IronJS.AutoWrapObject+AutoWrapEventArgs]' cannot be converted to type 'System.EventHandler`1[Node.net.Modules.Streams.NodeStream+DataEventArgs]'. </code></pre> <p>I have also tried using Invoke to dynamically use the constructor of e.EventHandlerType, but there's no way to pass the delegate definition to Invoke()'s parameter list (because there is no conversion from delegate to object).</p> <p>Is there a way I can use <a href="https://en.wikipedia.org/wiki/Reflection_%28computer_programming%29" rel="nofollow">reflection</a> to get around this problem?</p>
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    1. USPeter Mortensen
    1. USJune Rhodes
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    1. COAre you using .NET 4.0? If so you could try replacing the EventHandler<AutoWrapEventArgs> with the dynamic keyword. See if that helps you...
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      1. POUsing reflection to specify the type of a delegate (to attach to an event)?
      1. USBrian Dishaw
    2. CONope, it's .NET 3.5. I'll update the original question with that.
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      1. POUsing reflection to specify the type of a delegate (to attach to an event)?
      1. USJune Rhodes
    3. COHmm.. it's quite interesting that typeof(EventHandler<>).MakeGenericType(e.EventHandler.GetGenericArguments()[0]).GetConstructors()[0] returns "{Void .ctor(System.Object, IntPtr)}". I'm not particularly sure how a delegate matches up with that parameter list, but it's almost surely relevant to the solution.
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      1. POUsing reflection to specify the type of a delegate (to attach to an event)?
      1. USJune Rhodes
 

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