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POHow to implement a generic GetById method using Entity Framework 4 and the Repository Pattern?
 

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  1. POHow to implement a generic GetById method using Entity Framework 4 and the Repository Pattern?
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    <p>I have a generic repository and would like to implement a generic GetById method. This is my repository interface so far:</p> <pre><code>public interface IRepository&lt;T&gt; where T : EntityObject { void Add(T entity); void Delete(int id); void Delete(T entity); IEnumerable&lt;T&gt; Find(Expression&lt;Func&lt;T, bool&gt;&gt; predicate); T SingleOrDefault(Expression&lt;Func&lt;T, bool&gt;&gt; predicate); IEnumerable&lt;T&gt; GetAll(); T GetById(int id); void Save(); T Single(Expression&lt;Func&lt;T, bool&gt;&gt; predicate); } </code></pre> <p>I am using the Entity Framework 4.1. Lots of the solutions I found were using an abstract base class of interface for an IEntity class which the entities have to inherit from in order to perform the Id lookup.</p> <p>Instead of having to implement an interface for all my classes I was trying to use this bit of code:</p> <pre><code>T entity = _objectSet.Where( x =&gt; x.EntityKey.EntityKeyValues .Select(v =&gt; v.Value.Equals(id)).Count() == 1).First(); </code></pre> <p>However when trying to use the method I receive an exception:</p> <p><code>The specified type member 'EntityKey' is not supported in LINQ to Entities. Only initializers, entity members, and entity navigation properties are supported.</code></p> <p>Could someone tell me how I can get this to work?</p> <p><strong>Update 1</strong></p> <p>The members _objectContext and _context are declared like this:</p> <pre><code>private readonly ObjectContext _context; private readonly IObjectSet&lt;T&gt; _objectSet; </code></pre> <p>Thanks.</p>
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    1. COCheck this answer: http://stackoverflow.com/questions/5273416/entity-framework-simple-generic-getbyid-but-has-differents-pk-name/5278684#5278684 It contains exactly what you are looking for.
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      1. USLadislav Mrnka
 

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