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POProblems with DataContractSerializer - how to correctly serialize objects deriving from List<T>?
 

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  1. POProblems with DataContractSerializer - how to correctly serialize objects deriving from List<T>?
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    <p>Observe the following sample code:</p> <pre><code>namespace A { [Serializable] internal class ComplexObject&lt;T&gt; : List&lt;T&gt;, IEquatable&lt;ComplexObject&lt;T&gt;&gt; where T : IEquatable&lt;T&gt; { private T m_state; internal T State { get { return m_state; } set { m_state = value; } } public bool Equals(ComplexObject&lt;T&gt; other) { // Implementation is omitted to save space. } } public static class Program { public static void Main() { var obj = new ComplexObject&lt;int&gt;(); obj.State = 100; var stream = new MemoryStream(); var serializer = new DataContractSerializer(obj.GetType()); serializer.WriteObject(stream, obj); stream.Flush(); stream.Seek(0, SeekOrigin.Begin); var copy = (ComplexObject&lt;int&gt;)serializer.ReadObject(stream); Debug.Assert(obj.Equals(copy)); } } } </code></pre> <p>Note that <code>ComplexObject&lt;T&gt;</code> derives from <code>List&lt;T&gt;</code>. </p> <p>Anyway, the last assertion fails. Replacing <code>[Serializable]</code> with <code>[CollectionDataContract]</code> and attaching <code>[DataMember]</code> to <code>m_state</code> yields the same negative result.</p> <p>It is as though the <code>DataContractSerializer</code> notices that the class is a collection and chooses to ignore its other state.</p> <p>Please advice anyone how to solve this issue given that:</p> <ul> <li>I would like to make as few changes to <code>ComplexObject&lt;T&gt;</code> as possible</li> <li>I am stuck with <code>DataContractSerializer</code> for reasons irrelevant for this question</li> </ul> <p>Thanks a lot in advance.</p> <p><strong>EDIT:</strong></p> <pre><code>public bool Equals(ComplexObject&lt;T&gt; other) { if (!m_state.Equals(other.m_state) || Count != other.Count) { return false; } bool result = true; for (int i = 0; i &lt; Count &amp;&amp; (result = this[i].Equals(other[i])); ++i) { } return result; } </code></pre>
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    1. COThe assertion that is failing is based the Equals method whose implementation is omitted to save space. You'll have more chance of an answer if you can provide the implementation (or a simpler implementation that also fails).
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    2. CODone. Added the implementation in the body of the question.
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