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POado.net entity framework massive confusion
 

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  1. POado.net entity framework massive confusion
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    <p>I really hope you can help me as I am about to just throw my MVC/Entity Framework project in the bin and start a MVC/Linq project.</p> <p>I am building a forum as a project just to get to know MVC/Entity, and I have 4 tables which are all related.</p> <ul> <li>Forum_Category,</li> <li>Forum,</li> <li>Topic,</li> <li>Reply</li> </ul> <p>so there is a 1 to many on Category_ID between Forum_Category and Forum.</p> <p>1 to many on Forum_ID between forum and topic.</p> <p>and a 1 to many on Topic_ID between Topic and Reply.</p> <p>I understand that you can load up related data using</p> <pre><code>Dim F = (From forum in _DataContext.Forum.Include("Forum_Category") _ Where forum.Forum_ID = 1 _ Select forum).First </code></pre> <p>but what if I wanted to get the data for all the replys to a single topic, then load up the topic's forum and then the category?</p> <p>I managed to get slightly there with the code:</p> <pre><code>Dim FT = (From F In _dataContext.Topic.Include("Forum") _ Where F.TOPIC_STATUS = ForumSettings.FORUM_STATUS.Active _ Select F).First() Dim TRs = (From F In _dataContext.Topic_Reply _ Where F.Topic.TOPIC_ID = TopicID _ Select F).ToList() For Each TR As Topic_Reply In TRs FT.Topic_Reply.Add(TR) Next Return FT </code></pre> <p>But then when I tried to add a new Reply, I got the error: An object with the same key already exists in the ObjectStateManager. The ObjectStateManager cannot track multiple objects with the same key.</p> <p>I am totally lost now.</p>
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    1. USTim B James
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