Linq To SQL, UnitOfWork, Repository


S

shapper

Hello,

Lately I have been trying Entity Framework 3.5 but it does not support
Lazy Loading in a nice way.
There are a few hacks but they only gave me problems.

Is there a way to create a UnitOfWork, a BaseRepository and a
BaseService with LinqToSql?

I have done the following for EF:

public interface ISession {
void Commit();
void Dispose();
} // ISession

public partial class AppEntities : ISession {
public void Commit() {
SaveChanges();
} // Commit
public void Rollback() {
Dispose();
} // Rollback
} // AppEntities

public interface IRepository<T> {
void Create(T t);
void Delete(T t);
ObjectQuery<T> GetAll();
T GetById(Int32 id);
void Update(T t);
} // IRepository

public class Repository<T> : IRepository<T> {
private AppEntities _context;

public Repository(ISession session) {
if (session == null)
throw new ArgumentNullException("session");
_context = (AppEntities)session;
} // Repository

public void Create(T t) {
String table = typeof(T).Name;
_context.AddObject(table, t);
} // Create

public void Delete(T t) {
_context.DeleteObject(t);
} // Delete

public ObjectQuery<T> GetAll() {
String table = typeof(T).Name;
return _context.CreateQuery<T>(table);
} // GetAll

public T GetById(Int32 id) {
String table = typeof(T).Name;
EntityKey key = new EntityKey(_context.DefaultContainerName +
"." + table, "Id", id);
return (T)_context.GetObjectByKey(key);
} // GetById

public void Update(T t) {
String table = typeof(T).Name;
Int32 Id = GetPrimaryKeyValue(t);
T entity = GetById(Id);
entity = t;
_context.ApplyPropertyChanges(table, entity);
} // Update

private int GetPrimaryKeyValue(T t) {
Int32 id = 0;
PropertyInfo[] properties = typeof(T).GetProperties();
foreach (PropertyInfo p in properties) {
if (String.Compare(p.Name, "Id", true) == 0) {
String r = p.GetValue(t, null).ToString();
id = Int32.Parse(r);
break;
}
}
return id;
} // GetPrimaryKeyValue

} // Repository

public abstract class Service<TModel, T> where TModel : new() where
T : new() {

public Repository<T> repository;

protected Service(ISession session) {

repository = new Repository<T>(session);

TypeMap map = Mapper.FindTypeMapFor<T, TModel>();
if (map == null) {
Mapper.CreateMap<T, TModel>();
}

map = Mapper.FindTypeMapFor<TModel, T>();
if (map == null) {
Mapper.CreateMap<TModel, T>();
}
}

public virtual void Create(TModel tm) {
T t = Map(tm);
repository.Create(t);
} // Create

public virtual void Delete(T t) {
repository.Delete(t);
} // Delete

public virtual IEnumerable<TModel> GetAll() {
IQueryable<T> ts = repository.GetAll();
return Map(ts);
} // GetAll

public virtual TModel GetById(Int32 id) {
T t = repository.GetById(id);
return Map(t);
} // GetById

public virtual void Update(TModel tm) {
T t = Map(tm);
repository.Update(t);
} // Update

public virtual TModel Map(T t) {
return Mapper.Map<T, TModel>(t);
} // Map

public virtual T Map(TModel tm) {
return Mapper.Map<TModel, T>(tm);
} // Map

public virtual IEnumerable<TModel> Map(IQueryable<T> t) {
return Mapper.Map<IQueryable<T>, IEnumerable<TModel>>(t);
} // Map

public virtual IEnumerable<T> Map(IQueryable<TModel> tm) {
return Mapper.Map<IQueryable<TModel>, IEnumerable<T>>(tm);
} // Map
} // Service

public class ArticleService : Service<ArticleUI, Article> {

public ArticleService(ISession session) : base(session) {
} // ArticleService

public IEnumerable<ArticleUI> GetPublished() {
IQueryable<Article> articles = repository.GetAll().Where(a =>
a.Published == true);
return Map(articles);
IDictionary<Int32, String> b = new Dictionary<Int32, String>();

} // GetPublished

} // ArticleServices

Thanks,
Miguel
 
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S

shapper

Hello,

Lately I have been trying Entity Framework 3.5 but it does not support
Lazy Loading in a nice way.
There are a few hacks but they only gave me problems.

Is there a way to create a UnitOfWork, a BaseRepository and a
BaseService with LinqToSql?

I have done the following for EF:

  public interface ISession {
    void Commit();
    void Dispose();
  } // ISession

  public partial class AppEntities : ISession {
    public void Commit() {
      SaveChanges();
    } // Commit
    public void Rollback() {
      Dispose();
    } // Rollback
  } // AppEntities

  public interface IRepository<T> {
    void Create(T t);
    void Delete(T t);
    ObjectQuery<T> GetAll();
    T GetById(Int32 id);
    void Update(T t);
  } // IRepository

  public class Repository<T> : IRepository<T> {
    private AppEntities _context;

    public Repository(ISession session) {
      if (session == null)
        throw new ArgumentNullException("session");
      _context = (AppEntities)session;
    } // Repository

    public void Create(T t) {
      String table = typeof(T).Name;
      _context.AddObject(table, t);
    } // Create

    public void Delete(T t) {
      _context.DeleteObject(t);
    } // Delete

    public ObjectQuery<T> GetAll() {
      String table = typeof(T).Name;
      return _context.CreateQuery<T>(table);
    } // GetAll

    public T GetById(Int32 id) {
      String table = typeof(T).Name;
      EntityKey key = new EntityKey(_context.DefaultContainerName+
"." + table, "Id", id);
      return (T)_context.GetObjectByKey(key);
    } // GetById

    public void Update(T t) {
      String table = typeof(T).Name;
      Int32 Id = GetPrimaryKeyValue(t);
      T entity = GetById(Id);
      entity = t;
      _context.ApplyPropertyChanges(table, entity);
    } // Update

    private int GetPrimaryKeyValue(T t) {
      Int32 id = 0;
      PropertyInfo[] properties = typeof(T).GetProperties();
      foreach (PropertyInfo p in properties) {
        if (String.Compare(p.Name, "Id", true) == 0) {
          String r = p.GetValue(t, null).ToString();
          id = Int32.Parse(r);
          break;
        }
      }
      return id;
    } // GetPrimaryKeyValue

  } // Repository

  public abstract class Service<TModel, T> where TModel : new() where
T : new() {

    public Repository<T> repository;

    protected Service(ISession session) {

      repository = new Repository<T>(session);

      TypeMap map = Mapper.FindTypeMapFor<T, TModel>();
      if (map == null) {
        Mapper.CreateMap<T, TModel>();
      }

      map = Mapper.FindTypeMapFor<TModel, T>();
      if (map == null) {
        Mapper.CreateMap<TModel, T>();
      }
    }

    public virtual void Create(TModel tm) {
      T t = Map(tm);
      repository.Create(t);
    } // Create

    public virtual void Delete(T t) {
      repository.Delete(t);
    } // Delete

    public virtual IEnumerable<TModel> GetAll() {
      IQueryable<T> ts = repository.GetAll();
      return Map(ts);
    } // GetAll

    public virtual TModel GetById(Int32 id) {
      T t = repository.GetById(id);
      return Map(t);
    } // GetById

    public virtual void Update(TModel tm) {
      T t = Map(tm);
      repository.Update(t);
    } // Update

    public virtual TModel Map(T t) {
      return Mapper.Map<T, TModel>(t);
    } // Map

    public virtual T Map(TModel tm) {
      return Mapper.Map<TModel, T>(tm);
    } // Map

    public virtual IEnumerable<TModel> Map(IQueryable<T> t) {
      return Mapper.Map<IQueryable<T>, IEnumerable<TModel>>(t);
    } // Map

    public virtual IEnumerable<T> Map(IQueryable<TModel> tm) {
      return Mapper.Map<IQueryable<TModel>, IEnumerable<T>>(tm);
    } // Map
  } // Service

  public class ArticleService : Service<ArticleUI, Article> {

    public ArticleService(ISession session) : base(session) {
    } // ArticleService

    public IEnumerable<ArticleUI> GetPublished() {
      IQueryable<Article> articles = repository.GetAll().Where(a =>
a.Published == true);
      return Map(articles);
      IDictionary<Int32, String> b = new Dictionary<Int32, String>();

    } // GetPublished

  } // ArticleServices

Thanks,
Miguel

I was able to find an alternative solution for my problem.

Thank You,
Miguel
 

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