如何使用 LINQ 制作累积过滤器？答案

【问题标题】：How can I make a cumulative filter with LINQ?如何使用 LINQ 制作累积过滤器？
【发布时间】：2021-03-19 18:48:05
【问题描述】：

这是我的方法，我只过滤一个，我需要它们是累积的

private IQueryable<PublicationModel> FilterByTreatmentStatus(IQueryable<PublicationModel> selectedData, int? filterTreatmentOption)
        {
            if (filterTreatmentOption.HasValue)
            {
                switch (filterTreatmentOption)
                {
                    case (int)PublicationTreatStatus.NotTreated:
                        return selectedData.Where(x => x.PublicationStatus == 0);
                    case (int)PublicationTreatStatus.Treated:
                        return selectedData.Where(x => x.PublicationStatus == 1);
                    case (int)PublicationTreatStatus.TreatedWithoutProvidence:
                        return selectedData.Where(x => x.PublicationStatus == 2);
                    default:
                        return selectedData;
                }
            }

            return selectedData;
        }

【问题讨论】：

标签： c# asp.net linq

【解决方案1】：

你去 - 使用标志，所以你的枚举可以保存多个值

[Flags]
public enum FilterTreatmentOption
{
    NotTreated = 1,
    Treated = 2,
    TreatedWithoutProvidence = 4
}


private IQueryable<PublicationModel> FilterByTreatmentStatus(IQueryable<PublicationModel> selectedData, FilterTreatmentOption filterTreatmentOption)
{
    if (filterTreatmentOption.HasFlag(PublicationTreatStatus.NotTreated))
        selectedData = selectedData.Where(x => x.PublicationStatus == 0);
    if (filterTreatmentOption.HasFlag(PublicationTreatStatus.Treated))
        selectedData = selectedData.Where(x => x.PublicationStatus == 1);
    if (filterTreatmentOption.HasFlag(PublicationTreatStatus.TreatedWithoutProvidence))
        selectedData = selectedData.Where(x => x.PublicationStatus == 2);
    return selectedData;
}

【讨论】：