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POlinq 'range variable' problem
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  1. POlinq 'range variable' problem
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    copied!<p>I have a strange problem when deleteting records using linq, my suspicion is that it has something to do with the range variable (named <code>source</code>). After deleting a record all targets for a customer are retrieved using the following statement:</p> <pre><code>var q = from source in unitOfWork.GetRepository&lt;db_Target&gt;().Find() where source.db_TargetBase.db_Person.fk_Customer == customerID select source.FromLinq(); </code></pre> <p>where FromLinq is in extention method on db_target:</p> <pre><code>public static Target FromLinq(this db_Target source) { return new Target { id = source.id, LastModified = source.db_TargetBase.LastModified, ... } } </code></pre> <p>When a record is deleted both <code>db_Target</code> and <code>db_TargetBase</code> are deleted. When, for example, two users are deleting records, linq tries to retrieve a record for user2 which is deleted by user1, causing a crash on the <code>LastModified = source.db_TargetBase.LastModified</code> line because <code>db_TargetBase</code> is <code>null</code>.</p> <p>When using the following code the problem does not occure and only the non-deleted records are retrieved:</p> <pre><code>var q = from source in unitOfWork.GetRepository&lt;db_Target&gt;().Find() where source.db_TargetBase.db_Person.fk_Customer == customerID select new Target { id = source.id, LastModified = source.db_TargetBase.LastModified, ... }; </code></pre> <p>This spawns two questions:</p> <ol> <li>What is happening here? Am I making a copy of the range variable <code>source</code> because I'm using it in a extention method?</li> <li>How can I "wrap" the <code>return new Target</code> code? I am using this in multiple places and do not want to copy it every time. Making my code harder to maintain.</li> </ol> <p>TIA,</p> <p>JJ</p>
 

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