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POInheriting List<T> to implement collections a bad idea?
 

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    <p>I once read an article by Imaar Spaanjars on how to build 3 tier applications. (<a href="http://imar.spaanjaars.com/416/building-layered-web-applications-with-microsoft-aspnet-20-part-1" rel="nofollow noreferrer">http://imar.spaanjaars.com/416/building-layered-web-applications-with-microsoft-aspnet-20-part-1</a>) which has formed the basis of my coding for a while now. </p> <p>Thus I implement collections as he has done, by inheriting a <code>List&lt;T&gt;</code>. So if I have a class named Employee,to implement a collection I will also have a class Employees as below.</p> <pre><code>class Employee { int EmpID {get;set;} string EmpName {get;set;} } class Employees : List&lt;Employee&gt; { public Employees(){} } </code></pre> <p>I never really questioned this as it did the work for me. But now that I started trying out a few things I am not sure if this is the correct approach.</p> <p>e.g. if I want to get a subset from Employees, such as </p> <pre><code> Employees newEmployees = (Employees) AllEmployees.FindAll(emp =&gt; emp.JoiningDate &gt; DateTime.Now); </code></pre> <p>This throws a System.InvalidCastException . However, if I use the following then there is no Issue. </p> <pre><code>List&lt;Employee&gt; newEmployees = AllEmployees.FindAll(emp =&gt; emp.JoiningDate &gt; DateTime.Now); </code></pre> <p>So how do I implement Employees so that I dont have to explicitly use <code>List&lt;Employee&gt;</code> in my DAL or BLL? Or maybe how do I get rid of the InvalidCastexception?</p>
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