VB.NET Linq到對象相交返回對象

Question

如何從對象數組和字符串數組的交集中獲取對象的集合？

例如，我有對象（類人）的集合，並且名稱的字符串數組：

Public Class Person 
    Public lastName As String 
    Public firstName As String 
End Class 

Public Class Form1 
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load 
     Dim personArray As List(Of Person) 
     Dim p1 As Person = New Person("Bill", "Fitch") : personArray.Add(p1) 
     Dim p2 As Person = New Person("Randy", "Roberts") : personArray.Add(p2) 
     Dim p3 As Person = New Person("Miles", "Johnson") : personArray.Add(p3) 
     Dim p4 As Person = New Person("Sandy", "Smith") : personArray.Add(p4) 

     Dim arrayNames() As String = {"Jones", "Roberts", "Smith", "Teague"} 

     'The Linq code 
     Dim query = From myPerson In personArray 
        Where myPerson.lastName = arrayNames 
        Select myPerson 
    End Sub 
End Class 

當然LINQ的代碼不工作，但什麼LINQ的呢？

Answer 1

您可以使用包含：

Dim query = From myPerson In personArray 
       Where arrayNames.Contains(myPerson.lastName) 
       Select myPerson 

Answer 2

你可以使用一個連接：

Dim query = From p As Person In personArray 
      Join lastName As String In arrayNames On p.lastName Equals lastName 
      Select p 

這裏是完整的代碼，如果你想測試一下（我稍微改變了你的代碼，確保它編譯）。

Public Class Form1 
    Public Class Person 
    Public lastName As String 
    Public firstName As String 
    Sub New(firstName As String, lastName As String) 
     Me.lastName = lastName 
     Me.firstName = firstName 
    End Sub 
    End Class 

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load 
    Dim personArray As New List(Of Person)({ 
     New Person("Bill", "Fitch"), 
     New Person("Randy", "Roberts"), 
     New Person("Miles", "Johnson"), 
     New Person("Sandy", "Smith") 
    }) 

    Dim arrayNames() As String = {"Jones", "Roberts", "Smith", "Teague"} 

    Dim query = From p As Person In personArray 
       Join lastName As String In arrayNames On p.lastName Equals lastName 
       Select p 
    End Sub 
End Class