C＃实体框架6 - 如何从DbSet.RemoveRange方法获取计数

Question

如何从DbSet.RemoveRange方法获取计数？当我尝试使用Count()时，它会在保存更改时抛出错误

_dbFileManagementRepository.FileManagements.RemoveRange(_dbFileManagementRepository.FileManagements.Where(x => x.Id == serviceId && x.DateAdded < purgeDate)).Count();
_dbFileManagementRepository.SaveChanges();

当我像这样分配它时，在保存更改时不会删除任何内容

var records = _dbFileManagementRepository.FileManagements.RemoveRange(_dbFileManagementRepository.FileManagements.Where(x => x.Id == serviceId && x.DateAdded < purgeDate));
int purgeCount = records.Count();
_dbFileManagementRepository.SaveChanges();

当我运行它时，它删除就好了：

_dbFileManagementRepository.FileManagements.RemoveRange(_dbFileManagementRepository.FileManagements.Where(x => x.Id == serviceId && x.DateAdded < purgeDate));
_dbFileManagementRepository.SaveChanges();

Answer 1

使用RemoveRange无论你做什么都需要两个查询，所以这应该适用于你的情况：

var toBeRemoved = _dbFileManagementRepository.FileManagements.Where(x => x.Id == serviceId && x.DateAdded < purgeDate).ToList();
var removedCount = toBeRemoved.Count;
_dbFileManagementRepository.FileManagements.RemoveRange(toBeRemoved);
_dbFileManagementRepository.SaveChanges();