EF: Many tables with the same column - can I access to it without copying the code? - entity-framework

Question

I have some tables which stores the file's data, e.g TabA, TabB, TabC, ... TabX. Each of them has the same column FileTypeID.
For each table I need to use the extension method to get the rows depending of the condition of the FileTypeID column. To do so, I have an extension method like that:
public static class FilesTab_Extenders
{
public static IList<TabA> GetSpecificFiles(this EntityCollection<TabA> mc)
{
///
}
}
but, I don't want mindlessly clone the same code for the rest of tables. The only difference will be the parameter - this EntityCollection<TabB>, this EntityCollection<TabC> etc. So, is it somehow possible to make the universal code for that scenario ?

Answer 1

To me the easiest way to do this would be to use an interface. You would then have your partial classes implement this interface and use it in your extention method:
public interface IFileTypeable
{
Guid FileTypeId { get; set;}
}
Now you would create partial class files for each of your TabA, TabB, TabC, ... TabX that follow this template:
namespace MyDBContextNamespace
{
public partial class TabA : IFileTypeable
{
// no need to do anything, the property is already implemented on the original class file.
}
public partial class TabB : IFileTypeable
{
// no need to do anything, the property is already implemented on the original class file.
}
}
Finally your extention method would be changed to look like this:
public static IList<IFileTypeable> GetSpecificFiles(this EntityCollection<IFileTypeable> mc)
{
foreach (var item in mc)
{
Guid fileTypeId = item.FileTypeId;
}
}