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copied!<h2>JavaScriptSerializer serialization: IEnumerable -> JavaScript Array</h2> <p>When the JavaScriptSerializer is used, it automatically converts an IEnumerable (without IDictionary) type -- that covers List<> or anything derived from it -- into an array.</p> <h2>Deserialization: JavaScript Array -> IEnumerable -> Collection Object</h2> <p>Now, upon <strong>deserialization</strong> from JSON, the JavaScriptSerializer must take the array, create an IEnumerable, then create an object for the field by passing that IEnumerable into its constructor. </p> <h2>Constructing Collection object via Constructor</h2> <p>Now, for List<> you have a constructor overload that takes an IEnumerable. So if you put <code>List<Test></code> as the type of your component it creates it fine.</p> <h2>Constructors not inherited</h2> <p>However, TestCol does <strong>NOT</strong> have such a constructor! The reason why it worked with <code>List<Test></code> and not with <code>TestCol</code> (which derives from <code>List<Test></code>) is that the only thing that is <strong>not</strong> inherited between classes are constructors!</p> <p>Therefore, the JavaScriptSerializer does not have any way to construct a TestCol from an IEnumerable. So it fails silently.</p> <h2>Deserialize Array by Creating List, then Casting to Type</h2> <p>Now the JavaScriptSerializer may then attempt to create a <code>List<Test></code> from this <code>IEnumerable<Test></code>, and then try to cast it into a TestCol.</p> <h2>Possible Solution</h2> <p>Solution: Try putting in:</p> <pre><code>public TestCol () {} // Need this when you have another constructor public TestCol (IEnumerable<Test> list) : base(list) {} // Constructor that takes an IEnumerable public TestCol (IList<Test> list) : base(list) {} // Constructor that takes an IList </code></pre> <p>as your TestCol's constructors. </p> <p>And if it still doesn't work, implement an explicit type cast from <code>List<Test></code> to <code>TestCol</code>.</p> <pre><code>public static explicit operator TestCol(IList<Test> list) { return new TestCol(list); } </code></pre>

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