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POHow do I create a facade for identical LINQ 2 SQL tables?
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  1. POHow do I create a facade for identical LINQ 2 SQL tables?
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    copied!<p>I'm working with a 14-year old schema where a parent table (P) contains a type (8 possibilities) and location (3 possibilities) field that together point to one of twenty-four specific tables (A1, A2, A3, B1, B2, B3...), all with identical schemas for their type.</p> <p>I would like to create a generic way to access the specific tables but cannot seem to make it work.</p> <p>Let's say the parent table is called Document and two types of specific are (NewLetter, CurrentLetter, and HistoricLetters) and (NewBill, CurrentBill, and HistoricBills).</p> <pre><code> public interface ILetter { DateTime CreationDate { get; } } public interface IBill { DateTime BillDate { get; } } // The LINQ 2 SQL generated classes already implement the CreationDate property public partial class NewLetter : ILetter { } public partial class CurrentLetter : ILetter { } public partial class HistoricLetter : ILetter { } </code></pre> <p>Then in my code, I would like to be able to do this:</p> <pre><code> switch (type) { case 1: Table&lt;IBill&gt; specificBill; switch (location) { ... } case 2: Table&lt;ILetter&gt; specificTable; switch (location) { case 1: specificTable = dataContext.NewLetter as Table&lt;ILetter&gt;; break; case 2: specificTable = dataContext.CurrentLetter ... case 3: specificTable = dataContext.HistoricLetter ... } } </code></pre> <p>Or something similar. Unfortunately I can't cast <code>Table&lt;NewLetter&gt;</code> to <code>Table&lt;ILetter&gt;</code> even if NewLetter implements ILetter. Is there any way around this? I guess I'm basically trying to create a view in C#, as I don't have the permissions to create one in the db itself.</p>
 

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