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    <p>Though I don't know exactly why I bet that the entity framework doesn't like selecting <code>new</code> objects of the same type in the property you are writing your query off of. If my assumption is correct the following code should be equivalent to what you are trying to do:</p> <pre><code>public ActionResult Test() { using (MyEntities db = new MyEntities()) { var model = from c in db.Categories; return View(model.ToList()); } } </code></pre> <p>You would only need to select new objects when you are mapping the properties of your context's classes to another class (IE not one that is generated by the EF).</p> <p>I did a little more research into the issue, including duplicating it myself, according to the stack trace this is where the exception is thrown: <code>System.Data.Objects.ELinq.ExpressionConverter.CheckInitializerType(Type type)</code> Here is the source code for <code>CheckInitializerType</code> (<a href="http://reflector.webtropy.com/default.aspx/4@0/4@0/untmp/DEVDIV_TFS/Dev10/Releases/RTMRel/ndp/fx/src/DataEntity/System/Data/Objects/ELinq/ExpressionConverter@cs/1305376/ExpressionConverter@cs" rel="nofollow">found here</a>):</p> <pre><code> // Determines whether the given type is supported for materialization private void CheckInitializerType(Type type) { // nominal types are not supported TypeUsage typeUsage; if (_funcletizer.RootContext.Perspective.TryGetType(type, out typeUsage)) { BuiltInTypeKind typeKind = typeUsage.EdmType.BuiltInTypeKind; if (BuiltInTypeKind.EntityType == typeKind || BuiltInTypeKind.ComplexType == typeKind) { throw EntityUtil.NotSupported(System.Data.Entity.Strings.ELinq_UnsupportedNominalType( typeUsage.EdmType.FullName)); } } // types implementing IEnumerable are not supported if (TypeSystem.IsSequenceType(type)) { throw EntityUtil.NotSupported(System.Data.Entity.Strings.ELinq_UnsupportedEnumerableType( DescribeClrType(type))); } } </code></pre> <p>For reasons I haven't determined yet, if the object you are trying to project properties onto has the <code>BuiltInTypeKind</code> of <code>EntityType</code> or <code>ComplexType</code>, then projection is not supported. With my testing I discovered that I can project properties onto an entity that was generated with another <code>edmx</code> file, so the relationship with a given <code>ObjectContext</code> seems to boil down to the <code>System.Data.Objects.DataClasses.EdmEntityTypeAttribute</code> that decorates the generated Entity class.</p>
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    1. COHi Nathan, that does actually work but it retrieves all the data from the table. What I wanted, although my example here doesn't show this, is to select just a few columns and return their data. I have a much larger Articles table which has a lot of fields in it and there are times where I only need a couple of them. I didn't want to pull unnecessary data from the database. I was using the Category table as a simple test. :)
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    2. COI think I understand what you're trying to do, but it seems the crux of your issue is still selecting a new object that is generated by EF. If you only need a few columns you are probably best off with using a another class with only those properties you are concerned with (or at least just restrict it to the objects you are interested in, like `var model = from c in db.Categories where c.IsActive select c;` - at least that will just return the rows that meet your conditions.
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    3. COThanks Nathan. Sorry for the slow response. I appreciate your answer and the comments but I'm reluctant to accept your answer because it still doesn't tell me why this is the case.
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