FindPosts(this IDataFacade dataFacade, int?region, int?userId, int page, int itemsPerPage)
{
if (dataFacade == null)
{
throw new ArgumentNullException(nameof(dataFacade));
}
if (page < 0)
{
throw new ArgumentOutOfRangeException(nameof(page));
}
if (itemsPerPage <= 0)
{
throw new ArgumentOutOfRangeException(nameof(itemsPerPage));
}
// 构造查询
var query = dataFacade.Posts
.AsNoTracking()
.Where(e => e.IsRemoved == false);
if (region != null)
{
query = query.Where(e => e.PostRegionId == region.Value);
}
if (userId != null)
{
query = query.Where(e => e.AuthorId == userId.Value);
}
var indexEntities = await query.OrderByDescending(e => e.UpdateTime)
.Paginate(page, itemsPerPage)
.ToListAsync();
var contentEntities =
await dataFacade.FindPostContentEntities(indexEntities.Select(e => new ObjectId(e.ContentId)));
var contentDict = contentEntities.ToDictionary(e => e.Id);
return(indexEntities.Select(indexEntity =>
{
if (contentDict.TryGetValue(new ObjectId(indexEntity.ContentId), out var contentEntity))
{
return (indexEntity, contentEntity);
}
return (indexEntity, null);
}).ToList());
}
