使用 linq 过滤列表

Question

任何人都可以帮我完成这个过滤元素的功能吗

Public Sub adjectAllNormals()

    Dim qry As LinkedList(Of CElement) = From elm In Elements
              From id In SelectIDs()
              Where elm.ID = id

    Console.WriteLine(qry.Count)
End Sub

Answer 1

Linq 查询返回 IEnumerable(Of T)，而不是 LinkedList(Of T)...您可以尝试这样做：

Public Sub adjectAllNormals()

    Dim qry As IEnumerable(Of CElement) = From elm In Elements
              From id In SelectIDs()
              Where elm.ID = id
              Select elm

    Dim list As New LinkedList(Of CElement)(qry)
    Console.WriteLine(list.Count)
End Sub

Answer 2

Dim ids = SelectIDs().ToList()
Dim qry = From elm In Elements Where ids.Contains(elm.ID) select elm