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;       
    }
}