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POC# generics with linq search criteria
 

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    <p>I'm trying to make tiny helper method for simplify routine operations But on the sample:</p> <pre><code>public static int getEntityId&lt;Type, Entity&gt;(String name) where Entity: class { Type type = _db.GetTable&lt;Entity&gt;().SingleOrDefault(t =&gt; t.name == name); return 0; } </code></pre> <p>i get error:</p> <pre><code>Error 1 'Entity' does not contain a definition for 'name' and no extension method 'name' accepting a first argument of type 'Entity' could be found (are you missing a using directive or an assembly reference?) c:\work\asutp_migration\asutp_migration\Program.cs 89 62 asutp_migration </code></pre> <p>Actually, this is expected error, but how to solve this? All tables/classes i will use with this method have "name" field/property.</p> <p>UPD 1: according to advices i did this:</p> <pre><code>public partial class unit : IHasName { } interface IHasName { string name { get; } int id { get; } } public static int getEntityId&lt;Type, Entity&gt;(String name) where Entity: class, IHasName { Type type = _db.GetTable&lt;Entity&gt;().SingleOrDefault(t =&gt; t.name == name); return (type == null) ? type.id : 0; } </code></pre> <p>and with code:</p> <pre><code>int i = getEntityId&lt;unit&gt;("м"); Console.WriteLine(i); </code></pre> <p>i get exception:</p> <pre><code>Unhandled Exception: System.NotSupportedException: The mapping of interface member IHasName.name is not supported. </code></pre> <p>UPD 2: <a href="http://connect.microsoft.com/VisualStudio/feedback/details/344903/linq-to-sql-mapping-interface-member-not-supported-exception" rel="nofollow noreferrer">http://connect.microsoft.com/VisualStudio/feedback/details/344903/linq-to-sql-mapping-interface-member-not-supported-exception</a> i can't believe. is it related to my issue?</p> <p>UPD 3: yeah, seems it's VS issue: <a href="http://social.msdn.microsoft.com/Forums/en/linqtosql/thread/bc2fbbce-eb63-4735-9b2d-26b4ab8fe589" rel="nofollow noreferrer">http://social.msdn.microsoft.com/Forums/en/linqtosql/thread/bc2fbbce-eb63-4735-9b2d-26b4ab8fe589</a></p> <p>UPD 4:</p> <pre><code>public static int getEntityId&lt;Type&gt;(String name) where Type: class, IHasName { Type type = _db.GetTable&lt;Type&gt;().SingleOrDefault(t =&gt; t.name.Equals(name)); return (type != null) ? type.id : 0; } </code></pre> <p>so this is a solution, thank you all :-)</p>
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    2. COi'm trying to prevent duplication of methods like here http://pastie.org/808750
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