Given the following Interfaces:
interface IEntity
{
int Id{get;}
}
interface IPerson : IEntity
{
string Name{get;}
int Age{get;}
}
interface ITeacher : IPerson
{
string StaffId{get;}
}
interface IStudent : IPerson
{
string StudentId{get;}
string Courses{get;}
}
interface IRepository
{
T Get<T>(int id) where T : IEntity
}
I have the following classes in my namespace
public class EntityBase() : IEntity
{
int Id{get;set;}
}
public class Teacher : EntityBase, ITeacher{}
public class Sudent : EntityBase, IStudent{}
Currently I am implementing this IRepository as follows:
class Repository: IRepository
{
IDataContext Context{get;set;}
T Get<T>(int id) where T : EntityBase
{
if(typeof(T) == typeof(Teacher))
return Context.Get<ITeacher>(id);
if(typeof(T) == typeof(Sudent))
return Context.Get<ISudent>(id);
throw new Exception("Unknown Interface " + typeof(T).Name);
}
}
Is there a betterway of implementing this? Given that our Context has no knowledge of our data types (Teacher, Student), just its interfaces (ITeacher, IStudent).
Can something like this work?
class Repository: IRepository
{
T Get<T>(int id) where T : EntityBase
{
var MyInterface = FindInterface<T>();
return Context.Get<MyInterface>(id);
}
}
I think this will do:
class Repository: IRepository
{
IDataContext Context{get;set;}
T Get<T>(int id) where T : EntityBase
{
string[] interfaceList = new string[]
{ "ITeacher", "IStudent"};
Type interfaceType = null;
foreach (string s in interfaceList)
{
var types = typeof(T).FindInterfaces((x, y) => x.Name == y.ToString(), s);
if (types.Length > 0)
interfaceType = types[0];
}
if (interfaceType == null)
throw new Exception("Unknown Interface " + typeof(T).Name);
MethodInfo method = typeof(Context).GetMethod("Get");
MethodInfo generic = method.MakeGenericMethod(interfaceType);
var returnValue = generic.Invoke(Context, new object[] { id });
return (T)Convert.ChangeType(returnValue, typeof(T));
}
}
EDIT: As I don't know the name of your namespace, I have used the Name property to filter the interfaces. In real world usage I will suggest that you use FullName just to be sure, like this:
...
string[] interfaceList = new string[]
{ "MyNamespace.ITeacher", "MyNamespace.IStudent"};
...
var types = typeof(T).FindInterfaces((x, y) => x.FullName == y.ToString(), s);