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POLinq to Entities (EF 4.0) and group 2 unrelated tables into an aggregated object
 

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  1. POLinq to Entities (EF 4.0) and group 2 unrelated tables into an aggregated object
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    <p>I have 2 tables (Document and Message) that have no foreign key relation, but the table Message have the id column from Document as a column (bad design, I know..)</p> <p>Table Document: DocId, Name</p> <p>Table Message: MessageId, DocId, Value</p> <p>One document object can have zero or more Message objects</p> <p>I want to write a query that returns a list of an aggregated object called DocumentWithMessages:</p> <pre><code>public class DocumentWithMessages { Document Document {get;set;} List&lt;Message&gt; Messages {get;set;} } </code></pre> <p>The query should return all Documents (with or without a list of Messages)</p> <p>I started to write such a method but it gives me an exception:</p> <pre><code>public ICollection&lt;DocumentWithDocumentSplitMessages&gt; GetSplitJobsWithMessages() { var messages = (from dm in ObjectContext.DocumentSplitMessages select dm).ToList(); var jobs = from d in ObjectContext.Documents let msgs = messages.Where(dm =&gt; dm.DocID == d.DocID).ToList() select new DocumentWithDocumentSplitMessages() { Document = d, DocumentSplitMessages = msgs }; return jobs.ToList(); } </code></pre> <p>The exception is:</p> <p>System.NotSupportedException : LINQ to Entities does not recognize the method 'System.Collections.Generic.List<code>1[BraArkivDataModel.DocumentSplitMessage] ToList[DocumentSplitMessage](System.Collections.Generic.IEnumerable</code>1[BraArkivDataModel.DocumentSplitMessage])' method, and this method cannot be translated into a store expression.</p> <p>How do I write such a query?</p>
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    1. COIf you can change the code, why can't you change the EF model?
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      1. POLinq to Entities (EF 4.0) and group 2 unrelated tables into an aggregated object
      1. USGert Arnold
 

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