Question

我试图遍历一个匿名类型集合，但得到一个 System.MissingMemberException HResult=0x80131512 Message=重载解析失败，因为没有可访问的“ForEach”接受此数量的参数。并且无法确定原因。我成功使用 For Each 但无法使用 Lambda 表达式。

        Dim car As Object = {(New With {Key .Model = "Buick", .Color = "Blue"}),
    (New With {Key .Model = "Volvo", .Color = "Green"}),
    (New With {Key .Model = "Jeep", .Color = "Red"})}

    For Each item In car
        If item.Color = "Blue" Then Debug.Print(String.Format("{0} {1}", item.Model, item.Color))
    Next

    car.ForEach(Sub(x)
                    Debug.Print(String.Format("[0} {1}", x.model, x.color))
                End Sub)

Answer 1

ForEach 是 List(Of T) 的东西，而不是 LINQ 的东西..

    Dim cars = ({ New With {Key .Model = "Buick", .Color = "Blue"},
        New With {Key .Model = "Volvo", .Color = "Green"},
        New With {Key .Model = "Jeep", .Color = "Red"}
    }).ToList()

这将创建汽车作为一个匿名数组，然后使用 ToList 从中创建一个列表； ForEach 然后可用

注意：集合使用复数

Answer 2

感谢您为我指明了正确的方向，这是我正在寻找的工作示例。

Imports System
Imports System.Linq

Public Module Module1
    
    Public Sub Main()
        
        Dim cars = ({ New With { .Model = "Buick", .Color = "Blue"},
        New With { .Model = "Volvo", .Color = "Green"},
        New With { .Model = "Jeep", .Color = "Red"}
    })

        cars.AsEnumerable.ToList().ForEach(sub(x) 
                console.WriteLine(string.format("Model: {0}  Color: {1}", x.Model, x.Color ))
            End Sub)
    End Sub
End Module

VB.net 使用 Lambda 表达式迭代匿名类型集合

2 个答案: