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POCreate LINQ query at runtime to GroupBy in EntityFramework (with inheritance)
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  1. POCreate LINQ query at runtime to GroupBy in EntityFramework (with inheritance)
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    copied!<p>This is the scenario. I have the following three classes, they are defined in Entity Framework, i only define them here for the example:</p> <pre><code>public class Foo { public string Color { get; set; } } public class Bar : Foo { public string Height { get; set; } } public class Pipe : Foo { public string Width { get; set; } } </code></pre> <p>So, I have many Foo's, this is my base class, I want to be able to specify a propery, and do this query:</p> <pre><code> from e in Context.Foos group e.Color by e.Color into result select new { Value = result.Key, ValueCount = result.Count() } </code></pre> <p>This should end up with:</p> <p>Blue 2 Black 4 Yellow 2</p> <p>This works, however I want to specify this at run time, with the Property name 'Color' passed by the client. Also, I want to search the derived entities too. If i try to do </p> <pre><code> group e.Height by e.Height into result </code></pre> <p>It wont work because there is no Height in Foo, only in Bar. But the point is I <strong>ONLY</strong> want to return Bars, this should also be specified at runtime. This is the main problem I have been having. I cant do <code>Foos.OfType&lt;Bar&gt;.GroupBy(some dynamic stuff)</code> because I dont know the type to filter for at runtime.</p> <p>Would really appreciate some help on this matter.</p> <p><strong>EDIT</strong></p> <p>Basically, what i'm trying to do is this <a href="https://stackoverflow.com/questions/1465700/system-linq-dynamic-select-new-into-a-listt-or-any-other-enumerable">System.LINQ.Dynamic: Select(&quot; new (...)&quot;) into a List&lt;T&gt; (or any other enumerable collection of &lt;T&gt;)</a> but return Count instead of Sum at the end.</p>
 

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