Error: An expression tree may not contain a dynamic operation

c#, dynamic, linq, linq-to-entities

Solution

Unboxing the object will do the trick:

     int contentId = (int)o.ContentId;
     var image = context.CmsImagesContents.FirstOrDefault(img => img.ContentId == contentId);

For more info about 'boxing/unboxing' click here

Problem

I use Asp.Net 4 and C#, I use EF 4. I have this query, I receive an error: ``` An expression tree may not contain a dynamic operation ``` ``` dynamic o = e.Item.DataItem; var imagesContent = context.CmsImagesContents.FirstOrDefault(img => img.ContentId == o.ContentId); ``` It seems is imposible to Cast a Dynamic Type using a Lamba Expression. How I can fix the problem, and able to use my object `o in my Lamba`? Thanks PS: `e.Item.DataItem` is of Type `CmsContent` and `o.ContentId` is of type `Int`

Original source