查看Select distinct by two properties in a list可以使用具有两个属性的 DistinctBy 扩展方法。我试图将其转换为 vb.net,但我没有得到预期的结果
测试类:
Public Class Test
Public Property Id As Integer
Public Property Name As String
Public Overrides Function ToString() As String
Return Id & " - " & Name
End Function
End Class
测试方法:
Private Sub RunTest()
Dim TestList As New List(Of Test)
TestList.Add(New Test() With {.Id = 1, .Name = "A"})
TestList.Add(New Test() With {.Id = 2, .Name = "A"})
TestList.Add(New Test() With {.Id = 3, .Name = "A"})
TestList.Add(New Test() With {.Id = 1, .Name = "A"})
TestList.Add(New Test() With {.Id = 1, .Name = "B"})
TestList.Add(New Test() With {.Id = 1, .Name = "A"})
Dim Result As IEnumerable(Of Test)
Result = TestList.DistinctBy(Function(element) element.Id)
'1 - A
'2 - A
'3 - A
Result = TestList.DistinctBy(Function(element) element.Name)
'1 - A
'1 - B
Result = TestList.DistinctBy(Function(element) New With {element.Id, element.Name})
'1 - A
'2 - A
'3 - A
'1 - A
'1 - B
'1 - A
'Expected:
'1 - A
'2 - A
'3 - A
'1 - B
End Sub
在使用匿名类型的 vb.net 中这完全可能吗?做这样的事情:
Result = TestList.DistinctBy(Function(element) element.Id & "-" & element.Name)
正在工作,因此我猜我在这里缺少匿名类型中的相等性。