使用LINQ列出过滤

Question

所以我在代码中遇到了这个方法：

private void FilterBasedUponPermission(List<Data.Indications.SpWeb_SavedIndications1LightDataObject> list)
        {
            list.RemoveAll(item =>
                (item.Permission == Controllers.Indications.ICConstants.TradeType_LLH && !isLLH) ||
                (item.Permission == Controllers.Indications.ICConstants.TradeType_ALM && !isALM) ||
                (item.Permission == Controllers.Indications.ICConstants.TradeType_RealEstate && !isRE) ||
                (item.Permission == Controllers.Indications.ICConstants.TradeType_Auditor && !isAuditor));
        }

但是，在传入的列表中，某些permission值为null，并且它们将保留在已过滤的列表中。我希望它删除那些也没有权限集的项目，而不仅仅是那些与您作为用户的权限不匹配的项目。

谢谢！

Answer 1

只需添加一个item.Permission == null

list.RemoveAll(item => item.Permission == null ||
                (item.Permission == Controllers.Indications.ICConstants.TradeType_LLH && !isLLH) ||
                (item.Permission == Controllers.Indications.ICConstants.TradeType_ALM && !isALM) ||
                (item.Permission == Controllers.Indications.ICConstants.TradeType_RealEstate && !isRE) ||
                (item.Permission == Controllers.Indications.ICConstants.TradeType_Auditor && !isAuditor));

Answer 2

那些工作吗？

list.RemoveAll(item => !item.Permission.HasValue); // in case Permission is Nullable<T>
list.RemoveAll(item => item.Permission == null);

您可以在逻辑或（||）之后添加所有其他条件。

干杯， 的Matthias

Answer 3

private void FilterBasedUponPermission(List<Data.Indications.SpWeb_SavedIndications1LightDataObject> list)
        {
            list.RemoveAll(item =>
                (item.Permission == null) ||
                (item.Permission == Controllers.Indications.ICConstants.TradeType_LLH && !isLLH) ||
                (item.Permission == Controllers.Indications.ICConstants.TradeType_ALM && !isALM) ||
                (item.Permission == Controllers.Indications.ICConstants.TradeType_RealEstate && !isRE) ||
                (item.Permission == Controllers.Indications.ICConstants.TradeType_Auditor && !isAuditor));
        }