public void Handle(IEnumerable <ITrackedEntry> changedEntries)
{
var versionId = Guid.NewGuid();
var _changedEntries = changedEntries.Where(i => (i.State == EntityState.Added || i.State == EntityState.Modified) &&
typeof(IVersionedEntity).IsAssignableFrom(i.Entity.GetType()))
.ToArray();
foreach (var entry in _changedEntries)
{
var versionedEntity = (IVersionedEntity)entry.Entity;
if (entry.State == EntityState.Added)
{
versionedEntity.VersionId = Guid.NewGuid();
}
else if (entry.State == EntityState.Modified)
{
var entityType = versionedEntity.GetType();
/// Clone entity
var originalValues = entry.OriginalValues;
var originalEntity = (IVersionedEntity)originalValues.ToObject();
/// Assign new primary key
var property = entityType.GetProperty(EntityUtility.GetIdPropertyName(entityType));
property.SetValue(originalEntity, Guid.NewGuid());
/// Assign version
originalEntity.VersionId = versionId;
versionedEntity.PreviousVersionId = originalEntity.VersionId;
context.Add(originalEntity);
}
}
}
internal static Expression <Func <TEntity, bool> > GetIdExpression(Guid id)
{
var parameterExpression = Expression.Parameter(typeof(TEntity));
return(Expression.Lambda <Func <TEntity, bool> >(
Expression.Equal(
Expression.PropertyOrField(parameterExpression, EntityUtility.GetIdPropertyName(typeof(TEntity))),
Expression.Constant(id, typeof(Guid)))
, parameterExpression
));
}
public virtual TEntity GetById <TId, TProperty>(TId id, params Expression <Func <TEntity, TProperty> >[] includes)
{
var query = GetQuery(includes);
var entityType = typeof(TEntity);
var parameter = Expression.Parameter(entityType);
var left = Expression.Property(parameter, EntityUtility.GetIdPropertyName(entityType));
var right = Expression.Constant(id);
var body = Expression.Equal(left, right);
var predicate = Expression.Lambda <Func <TEntity, bool> >(body, parameter);
return(query.SingleOrDefault(predicate));
}
private void InterceptPrimaryKey(DbEntityEntry entityEntry)
{
if (entityEntry.State == EntityState.Added)
{
var entity = entityEntry.Entity;
var entityType = entity.GetType();
var property = entityType.GetProperty(EntityUtility.GetIdPropertyName(entityType));
var value = property.GetValue(entity);
if (value.GetType() == typeof(Guid))
{
var guid = (Guid)value;
if (guid == Guid.Empty)
{
property.SetValue(entity, Guid.NewGuid());
}
}
}
}