Linq Group on Multiple Fields - VB.NET,Anonymous,Key

Question

我很难过.我需要帮助.我有一个带有重复患者地址数据的DTO对象.我只需要获得唯一的地址.

Dim PatientAddressDto = New List(Of PatientAddress)

{Populate PatientAddressDto with lots of duplicate data}

PatientAddressDto = (From d In PatientAddressDto
                    Group d By PatientAddressDtoGrouped = New PatientAddress With {
                                                              .Address1 = d.Address1,
                                                              .Address2 = d.Address2,
                                                              .City = d.City,
                                                              .State = d.State,
                                                              .Zip = d.Zip
                                                              }
                  Into Group
                  Select New PatientAddress With {
                                                  .Address1 = PatientAddressDtoGrouped.Address1,
                                                  .Address2 = PatientAddressDtoGrouped.Address2,
                                                  .City = PatientAddressDtoGrouped.City,
                                                  .State = PatientAddressDtoGrouped.State,
                                                  .Zip = PatientAddressDtoGrouped.Zip
                                                  }).ToList()

我试过以下没有运气:

PatientAddressDto = (From d In PatientAddressDto
                    Select New PatientAddress With {
                                                  .Address1 = d.Address1,
                                                  .Address2 = d.Address2,
                                                  .City = d.City,
                                                  .State = d.State,
                                                  .Zip = d.Zip
                                                    }).Distinct     

并且

PatientAddressDto = PatientAddressDto.GroupBy(Function(p) New PatientAddress With {
                                                  .Address1 = p.Address1,
                                                  .Address2 = p.Address2,
                                                  .City = p.City,
                                                  .State = p.State,
                                                  .Zip = p.Zip
                                                    })

Answer 1

您可以使用匿名类型并使用Key关键字,以使相等的行为符合您的预期(C#不需要).

通过指定Key前缀并删除PatientAddress用法来更改分组:

Group d By PatientAddressDtoGrouped = New With {
    Key .Address1 = d.Address1,
    Key .Address2 = d.Address2,
    Key .City = d.City,
    Key .State = d.State,
    Key .Zip = d.Zip
}

Answer 2

我发现以下代码可以工作，它基本上完成了我想要的分组，并将新对象填充为 PatientAddress 类型，因此消除了匿名对象和关键字 Key 的使用。

也许有人可以解释一下，但目前我还不能。祝你今天过得愉快。

Dim PatientAddressDto = New List(Of PatientAddress)

{Populate PatientAddressDto with lots of duplicate data}

PatientAddressDto = (From d In PatientAddressDto
                    Group d By d.Address1,
                                d.Address2,
                                d.City,
                                d.State,
                                d.Zip Into g =
                    Group Let grp = New PatientAddress With {.Address1 = Address1,
                                                                .Address2 = Address2,
                                                                .City = City,
                                                                .State = State,
                                                                .Zip = Zip}
                    Select grp).ToList()