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POEntity Framework POCO T4 sometimes creates an EntityCollection and sometimes creates a FixUpCollection
 

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  1. POEntity Framework POCO T4 sometimes creates an EntityCollection and sometimes creates a FixUpCollection
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    <p>I've run into a strange issue with the Entity Framework POCOs created by the POCO T4 templates - for some objects their collection properties are created as an <code>EntityCollection</code>, and for others they're created as a <code>FixUpCollection</code>.</p> <p>I'm finding this with three classes which model a product hierarchy; <code>ProductGroup</code>, <code>Platform</code> and <code>Product</code>. Each <code>ProductGroup</code> has a collection of <code>Platform</code>s, and each <code>Platform</code> has a collection of <code>Product</code>s. All the relationships are bi-directional. The collection getters and setters are exactly the same for each class because they're generated by the T4 template, so they all look (e.g.) like this:</p> <pre><code>public virtual ICollection&lt;Platform&gt; Platforms { get { if (_platforms == null) { var newCollection = new FixupCollection&lt;Platform&gt;(); newCollection.CollectionChanged += FixupPlatforms; _platforms = newCollection; } return _platforms; } set { ... } } </code></pre> <p>The funny thing is, <em>all</em> the collections on <code>Product</code> and <code>Platform</code> are created as <code>EntityCollection</code>s, and <em>all</em> the collections on <code>ProductGroup</code> are created as <code>FixUpCollection</code>s. i.e. when the code first enters the getter of (e.g.) <code>Platform.Products</code>, the <code>_products</code> field is already populated with an <code>EntityCollection</code>, but when it first enters the getter shown above, <code>_platforms</code> is null and a <code>FixupCollection</code> is created and subsequently populated. Lazy-loading is working in both cases, it's just working in two different ways.</p> <p>The <code>Entities</code> object has lazy-loading and proxy creation enabled. <code>Product</code>, <code>Platform</code> and <code>CoreProduct</code> objects are all dynamic EF proxies in the <code>Entity.DynamicProxies</code> namespace. I've tried eager loading the <code>Platform</code> and <code>ProductGroup</code>, which made no difference. I can't see any difference in how the classes are set up in the model viewer.</p> <p>This is causing me a headache because one of the collections on <code>ProductGroup</code> contains thousands of objects, and I want to query that collection. As far as I know (please do correct me if I'm wrong) I can't query a <code>FixUpCollection</code> without loading all the objects into memory, which is not the case for an <code>EntityCollection</code> because I can use <a href="http://msdn.microsoft.com/en-us/library/bb896438.aspx" rel="nofollow"><code>CreateSourceQuery()</code></a>. Has anyone seen this behaviour before? Is there some setting I'm missing somewhere? Any pointers or help would be much appreciated.</p>
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    1. USSteve Wilkes
    1. USSteve Wilkes
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      1. POEntity Framework POCO T4 sometimes creates an EntityCollection and sometimes creates a FixUpCollection
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    1. COI am curious as to what template you are using that creates this issue. I am using the POCO templates from http://visualstudiogallery.msdn.microsoft.com/23df0450-5677-4926-96cc-173d02752313 - and they don't seem to create either of these object types. Are you using a template from a different source?
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      1. POEntity Framework POCO T4 sometimes creates an EntityCollection and sometimes creates a FixUpCollection
      1. USTroy Alford
    2. COI'm pretty sure those are the ones I was using - the site notes that "the POCO generator has been updated", so maybe it was an older version... it's the ModelGenerator.tt file which contains the definition for the `FixUpCollection` class.
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      1. USSteve Wilkes
 

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