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POSimple way to return anonymous types (to make MVC using LINQ possible)
 

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    <p>I'd like to implement MVC while using LINQ (specifically, LINQ-to-entities). The way I would do this is have the Controller generate (or call something which generates) the result-set using LINQ, then return that to the View to display the data. The problem is, if I do:</p> <pre><code>return (from o in myTable select o); </code></pre> <p><strong>All</strong> the columns are read from the database, even the ones (potentially dozens) I don't want. And - more importantly - I <em>can't</em> do something like this:</p> <pre><code>return (from o in myTable select new { o.column }); </code></pre> <p>because there is no way to make anonymous types type-safe! I know for sure there is no nice, clean way of doing this in 3.5 (<a href="http://tomasp.net/blog/cannot-return-anonymous-type-from-method.aspx" rel="nofollow noreferrer">this</a> is not clean...), <strong>but what about 4.0? Is there anything planned, or even proposed?</strong> Without something like duck-typing-for-LINQ, or type-safe anonymous return values (it seems to me the compiler should certainly be capable of that), it appears to be nearly impossible to cleanly separate the Controller from the View.</p>
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    1. UStereško
    1. USBlueRaja - Danny Pflughoeft
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    1. COWhen you are working with a orm you should get used to the thought of having the sql select all columns of a table. If you write queries that selects only a few you might just as well be using sql in the first place. If you have dozens of properties on your objects then that is your problem. Your objects should be smaller and you should think about how you can fix that. Anonymous types should not be passed around, specially not as models to a view.
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      1. USMattias Jakobsson
    2. CO@Mattias: Unfortunately, life is not so simple. For example, consider the case where I select a few columns from different tables, including an array of objects selected using an inner-LINQ query. As far as I'm aware, there's no way to return that as a single EF object - it *has* to be a new type, and defining a new concrete type for every query like this is ridiculously cumbersome.
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      1. USBlueRaja - Danny Pflughoeft
    3. COSounds to me like you have a pretty bad model. Your object should have the references that it needs and you can just use the "Include()" method in EF (to eagerly load that data). If you stop thinking about the data as different columns in different tables, and more about your model (more OO) it will most likely be a lot easier to work with. Bottom line: If you feel the need to pass around anonymous types you are most likely doing something else wrong.
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      1. USMattias Jakobsson
 

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