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    <p>There is to my knowledge no easy way to achieve this, however have a look at PredicateBuilder, which does solve some of these issues: <a href="http://www.albahari.com/nutshell/predicatebuilder.aspx" rel="nofollow noreferrer">http://www.albahari.com/nutshell/predicatebuilder.aspx</a>. </p> <p>The basic idea is that you define interfaces with the common properties, which allows you to define generic expressions constrained to that interface.</p> <p>Start by definining these interfaces:</p> <pre><code>public interface IHaveItem { Item Item {get;} } public interface IDateVisible { DateTime? DateVisible {get;} } </code></pre> <p>This will allow you to write the query expressions in a generic way, obtaining at least some reuse:</p> <pre><code>public static Expression&lt;Func&lt;T,bool&gt;&gt; IsVisible&lt;T&gt;(DateTime now) where T:IHaveItem { return x =&gt; x.Item.DateVisible != null &amp;&amp; x.Item.DateVisible &lt; now; } </code></pre> <p>You will still not be able to easily achieve reuse between expressions like <code>x.DateVisible</code> and <code>x.Item.DateVisible</code> however.</p> <p>UPDATE: it turns out that 'unnecessary' cast operations are being added in the generated expression tree, which are then not supported by the entity framework provider when translating to SQL.</p> <p>You can apply a similar trick as the one in <a href="https://stackoverflow.com/questions/9120593/iqueryablet-with-entityobject-using-generics-interfaces-possible">this question</a> to remove these unnecessary cast operations 'manually'. Becomes a bit hairy though IMHO...</p>
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    1. COInteresting... thanks Jeroenh. I'll take a look at that. I did try adding an IEntityWithItem interface to my classes, and creating an expression that was - but EF was throwing the error 'LINQ to Entities only supports casting Entity Data Model primitive types'. Would the same thing not happen here?
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    2. COCan you show the code that threw this error? You shouldn't need the cast...
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    3. COI've updated the question with what I tried. It onlt differs in that I haven't added an interface for the date property - just the Item. Would this make a difference?
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