Question

Private Sub UpdateListBox(message As String)
    Dim beeGroups As IOrderedEnumerable(Of IGrouping(Of BeeState, Bee)) = From beeGroup In From bee In Me.world.BeesGroup bee By bee.CurrentStateOrder By beeGroup.KeybeeGroup
    Me.listBox1.Items.Clear()

    For Each beeGroup As IGrouping(Of BeeState, Bee) In beeGroups
        Dim s As String
        s = If(beeGroup.Count() = 1, String.Empty, "s")

        Me.listBox1.Items.Add(Convert.ToString(beeGroup.Key) & ": " & beeGroup.Count() & " bee" & s)

        If beeGroup.Key <> BeeState.Idle OrElse beeGroup.Count() <> Me.world.Bees.Count() OrElse Me.framesRun <= 0 Then
            Continue For
        End If

        Me.listBox1.Items.Add("Simulation ended: all bees are idle")
        Me.toolStripButtonStartSimulation.Text = "Simulation ended."
        Me.statusStrip1.Items(0).Text = "Simulation ended"
        Me.timer1.Enabled = False
    Next
End Sub

在将c#项目转换为vb.net时，我完全坚持这个错误。

我知道c#就像这样

IOrderedEnumerable<IGrouping<BeeState, Bee>> beeGroups = from bee in this.world.Bees
                                                                 group bee by bee.CurrentState
                                                                 into beeGroup orderby beeGroup.Key select beeGroup;

但是一旦转换为vb.net，它会尝试用尽可能少的声明来说明一行中的所有内容。

虽然也在c#，但你可以逃脱 c#：

foreach (IGrouping<BeeState, Bee> beeGroup in beeGroups)

vb.net尝试在其内部声明for语句：

For Each group As var In beeGroups

Answer 1

Private Sub UpdateListBox(message As String)
    Dim beeGroups = From bee In Me.world.Bees
                    Group By bee.CurrentState Into beeGroup = Group
                    Order By beeGroup.Key

    Me.listBox1.Items.Clear()

    For Each beeGroup In beeGroups
        Dim beeCount = beeGroup.Count ' to avoid reevaluation
        Dim s = If(beeCount >= 1, String.Empty, "s")

        Me.listBox1.Items.Add(Convert.ToString(beeGroup.Key) & ": " & beeCount & " bee" & s)

        If beeGroup.Key <> BeeState.Idle OrElse beeCount <> Me.world.Bees.Count OrElse Me.framesRun <= 0 Then
            Continue For
        End If

        Me.listBox1.Items.Add("Simulation ended: all bees are idle")
        Me.toolStripButtonStartSimulation.Text = "Simulation ended."
        Me.statusStrip1.Items(0).Text = "Simulation ended"
        Me.timer1.Enabled = False
    Next
End Sub

Answer 2

你的每个人＆＃39;语句是正确的（您的C＃和VB版本都在循环头中声明了迭代器变量），但是VB LINQ查询应该是：

Dim beeGroups As IOrderedEnumerable(Of IGrouping(Of BeeState, Bee)) = From bee In Me.world.Bees
                                                                      Group bee By bee.CurrentState Into beeGroup = Group
                                                                      Order By CurrentState
                                                                      Select beeGroup

或用户选项推断：

Dim beeGroups = From bee In Me.world.Bees
                Group bee By bee.CurrentState Into beeGroup = Group
                Order By CurrentState
                Select beeGroup

IOrderedEnumerable to vb.net IOrderedEnumerable Conversion

2 个答案: