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| public class Entity
{
public Guid Id { get; set; }
}
public class Product : Entity
{
public virtual string Reference { get; set; }
public virtual string Name { get; set; }
public virtual string Description { get; set; }
}
public interface IRepository<T> where T : Entity
{
bool Create(T entity);
T Read(Guid id);
bool Update(T entity);
bool Delete(Guid id);
}
public abstract class SqlRepositoryBase<T> : IDisposable, IRepository<T> where T : Entity, new()
{
protected SqlConnection Connection { get; }
protected SqlRepositoryBase(SqlConnection connection)
{
Connection = connection;
connection.Open();
}
#region Default CRUD implementation
// Uses reflection to automap class name and property names to table name and column names respectively
// These may be overided with more appropriate versions
public virtual bool Create(T entity)
{
if (entity.Id == Guid.Empty) entity.Id = Guid.NewGuid();
var mapping = ReflectionHelper.SelectMappingProperties<T>().ToList();
var parameters = mapping.Select(p => $"{p.Name} = @{p.Name}").ToArray();
var values = string.Join(", ", parameters);
var sql = $"INSERT INTO {typeof(T).Name} VALUES ({values})";
SqlTransaction tr = null;
try
{
var command = Connection.CreateCommand();
command.CommandType = CommandType.Text;
command.CommandText = sql;
mapping.ForEach(p => command.Parameters.AddWithValue("@" + p.Name, p.GetValue(entity)));
tr = Connection.BeginTransaction();
command.Transaction = tr;
var result = command.ExecuteNonQuery();
tr.Commit();
return result > 0;
}
catch
{
tr?.Rollback();
return false;
}
finally { tr?.Dispose(); }
}
public virtual bool Delete(Guid id)
{
throw new NotImplementedException();
}
public virtual T Read(Guid id)
{
if (id == Guid.Empty) return null;
var sql = $"SELECT * FROM {typeof(T).Name} WHERE Id = @Id";
var command = Connection.CreateCommand();
command.CommandType = CommandType.Text;
command.CommandText = sql;
var reader = command.ExecuteReader();
if (!reader.NextResult()) return null;
var entity = new T();
ReflectionHelper.SelectMappingProperties<T>().ToList().ForEach(p => p.SetValue(entity, reader[p.Name]));
return entity;
}
public virtual bool Update(T entity)
{
throw new NotImplementedException();
}
#endregion
#region IDisposable
private bool _disposed = false;
public void Dispose()
{
Dispose(true);
GC.SuppressFinalize(this);
}
protected virtual void Dispose(bool disposing)
{
if (_disposed) return;
if (disposing) { Connection.Dispose(); }
_disposed = true;
}
~SqlRepositoryBase() { Dispose(false); }
#endregion
}
public interface IProductRepository : IRepository<Product>
{
Product FindByReference(string reference);
}
public class ProductSqlRepository : SqlRepositoryBase<Product>, IProductRepository
{
public ProductSqlRepository(SqlConnection connection) : base(connection) { }
public Product FindByReference(string reference)
{
var sql = "SELECT Id FROM Product WHERE Reference = @Reference";
var command = Connection.CreateCommand();
command.CommandType = CommandType.Text;
command.CommandText = sql;
command.Parameters.AddWithValue("@Reference", reference);
var reader = command.ExecuteReader();
if (!reader.NextResult()) return null;
var id = (Guid)reader["Id"];
return Read(id);
}
}
public static class ReflectionHelper
{
public static IEnumerable<PropertyInfo> SelectMappingProperties<T>()
{
return SelectMappingProperties(typeof(T));
}
public static IEnumerable<PropertyInfo> SelectMappingProperties(Type t)
{
return t.GetProperties(BindingFlags.Instance | BindingFlags.Public).Where(p => p.CanRead && p.CanWrite).ToArray();
}
} |
Problème de design, comment dériver une méthode static ?
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