Question

我有一个如下的集合

Private _bankRates As Dictionary(Of RateSourceBank.Key, RateSourceBank)

RateSourceBank.Key只是

Public Class Key
    Public RateType As String
    Public EffectiveDate As DateTime
End Class

如何检索每个RateType有多个EffectiveDate的子集_bankRates？

不幸的是，我发现所有类似的例子都在C＃中，而且我喜欢LINQ翻译有点不那么简单，特别是当涉及到语法组时，例如查询以下

Dim ratesWithDuplicates = From rates In _bankRates
                          Group rates By rates.Key.RateType
                          Into grp()
                          Where grp.Count > 1

我收到错误：

在此上下文中无法访问方法'grp'的定义

Answer 1

以下是您正在寻找的代码段

Dim ratesWithDuplicates =
    From rates In _bankRates
    Group rates By rates.Key.RateType Into Group
    Where Group.Count() > 1

表达式/ keyword Group表示集合。您可以使用name = Group语法

为其指定不同的名称

Dim ratesWithDuplicates =
    From rates In _bankRates
    Group rates By rates.Key.RateType Into someName = Group
    Where someName.Count() > 1

使用复杂类型返回字典子集作为Linq的键

1 个答案: