Question

I have an abstract class that other classes are inheriting this.

public abstract class GenericAccess<TEntity>
{
    public static IList<TEntity> GetObjectListFromArray(int[] IDs)
    {
        //Your help need is here.
    }
}

public class Doors : GenericAccess<DoorEntity>
{

}

public class DoorEntity
{
    public int Id { get; set; }
    public string Name { get; set; }
}

I need to create a generic method so when I can for example

IList<DoorEntity> Doors.GetObjectListFromArray(int[] {1,2,3,4,5});

it will return an IList having all the objects in it with the property Id loaded with the value passed. In the above example it will return a list with 5 items in the list with the Id of DoorEntity loaded.

Answer 1

Use an interface or a base class…

With interface:

public abstract class GenericAccess<TEntity> where TEntity : IEntity, new()
{
    public static IList<TEntity> GetObjectListFromArray(int[] IDs)
    {
        return IDs.Select(id => new TEntity { Id = id }).ToList();
    }
}

public class Doors : GenericAccess<DoorEntity>
{

}

public class DoorEntity : IEntity
{
    public int Id { get; set; }
    public string Name { get; set; }
}

public interface IEntity
{
    int Id { get; set; }
    string Name { get; set; }
}

With a base class:

public abstract class GenericAccess<TEntity> where TEntity : Entity, new()
{
    public static IList<TEntity> GetObjectListFromArray(int[] IDs)
    {
        return IDs.Select(id => new TEntity { Id = id }).ToList();
    }
}

public class Doors : GenericAccess<DoorEntity>
{

}

public class DoorEntity : Entity
{

}

public abstract class Entity
{
    public int Id { get; set; }
    public string Name { get; set; }
}