I currently have a complete generic repository but I'm missing one feature and that is to use
Include() and Find()
together.
So now I have:
public E FindById<E>(int id) where E : class
{
return DataContext.Set<E>().Find(id);
}
called using
var person = PersonRepo.FindById<Person>(personId);
I would like to have something similar to:
var person = PersonRepo.FindByIdWithIncludes<Person>(personId,new[]{"State.Address"});
So, something along this lines (this is only a test):
public E FindByIdWithIncludes<E>(int id, string[] includes) where E : class
{
var entitySet = DataContext.Set<E>();
DbQuery<E> entityQuery;
foreach (var include in includes)
{
entityQuery = entitySet.Include(include);
}
return entityQuery.Find(id); //this is were it breaks
}
Is it possible?
You cannot use Find
directly - Find
doesn't work with includes. You must use SingleOrDefault
.
First you need to define interface for your entities to expose their key.
public interface IEntityWithId
{
public int Id { get; set; }
}
Next you can write simple method with constrain to get access to the key:
public E FindByIdWithIncludes<E>(int id, string[] includes)
where E : class, IEntityWithId
{
IQueryable<E> entityQuery = DataContext.Set<E>();
foreach (var include in includes)
{
entityQuery = entityQuery.Include(include);
}
return entityQuery.SingleOrDefault(e => e.Id == id);
}
Btw. you can use strongly typed includes - here is an example.
You could go also the other way around, to use Find
, but in combination with Load
. In some cases might be better performing than Include-SingleOrDefault
, but it really depends on the scenario.
Non-generic example:
private User GetByUID(int uID, bool includeDetails = false, bool includeAddresses = false)
{
var result = context.Users.Find(uID);
if (includeDetails)
{
// load user-details (1:1 relation)
context.Entry(result)
.Reference<UserDetails>(us => us.UserDetails)
.Load();
}
if (includeAddresses)
{
// load user-addresses (1:m relation)
context.Entry(result)
.Collection(us => us.Addresses)
.Load();
}
return result;
}
Should not be difficult to make it generic to your needs.
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