基于VB.NET(XML)的三层联动菜单，有人会做吗？

[jonical]

<?xml version="1.0" encoding="utf-8"?>
<Config>
	<Root Level="0" Index="0" Code="A" Name="方案1">
		<Solution Level="1" Index="0" Code="A1" Name="默认配置1">
				<Bind Level="2" Index="0" Code="A1A" Name="声音1"/>
				<Bind Level="2" Index="1" Code="A1B" Name="回音1"/>
		</Solution>
		<Solution Level="1" Index="1" Code="A2" Name="默认配置2">
				<Bind Level="2" Index="0" Code="A2A" Name="声音2"/>
				<Bind Level="2" Index="1" Code="A2B" Name="回音2"/>
		</Solution>
	</Root>
	<Root Level="0" Index="1" Code="B" Name="方案2">
		<Solution Level="1" Index="0" Code="B1" Name="默认配置1">
				<Bind Level="2" Index="0" Code="B1A" Name="声音1"/>
				<Bind Level="2" Index="1" Code="B1B" Name="回音1"/>
		</Solution>
		<Solution Level="1" Index="1" Code="B2" Name="默认配置2">
				<Bind Level="2" Index="0" Code="B2A" Name="声音2"/>
				<Bind Level="2" Index="1" Code="B2B" Name="回音2"/>
		</Solution>
	</Root>
</Config>

以上是Xml文件的结构体，在程序根目录存放。
之前发了一帖子，没正确答案。
想实现菜单的三级联动效果。如何实现？

[jonical]

界面上有三个combobox控件，combobox1显示“方案1”、“方案2”、“方案N”。 第二个combobox显示“默认配置1”、“默认配置2”、“默认配置N”。 第三个combobox显示“声音1”、“声音2”、“声音N” 如何实现？VB.NET不支持linq语法。工具VS2019或者VS2010

[hztltgg]

VB.NET 怎么可能不支持 Linq语法，事实上vb.net 对xml的查询比c#功能更强

[jonical]

读是能读，但是没办法做菜单的三级联动，比如省、市、区。比如选定某一区之后，再按照一个值读取相应的code值，这是VB.NET没法办到的，不太灵活。

[骷髅会-北极熊]

你的XML文件怎么存发都不是问题，
读取XML的就不在这里写了，我提供一下后续的数据处理，类名XMLMsg内容如下：

Public Class XMLMsg
    Public Property Level() As String
    Public Property Index() As String
    Public Property Code() As String
    Public Property Name() As String

End Class

第一步，全局变量三个：
Dim MsgLsit As New List(Of XMLMsg)
Dim Com1 As New List(Of XMLMsg)
Dim Com2 As New List(Of XMLMsg)
Dim Com3 As New List(Of XMLMsg)
第二步，在窗口加载的时候你是读XML，我就不读取了，在Load事件如下代码如下：

Dim tCond As New XMLMsg
        tCond.Level = "0"
        tCond.Index = "0"
        tCond.Code = "A"
        tCond.Name = "方案1"
        MsgLsit.Add(tCond)
        tCond = New XMLMsg
        tCond.Level = "1"
        tCond.Index = "0"
        tCond.Code = "A1"
        tCond.Name = "1-默认配置1"
        MsgLsit.Add(tCond)
        tCond = New XMLMsg
        tCond.Level = "2"
        tCond.Index = "0"
        tCond.Code = "A1A"
        tCond.Name = "1-声音1"
        MsgLsit.Add(tCond)
        tCond = New XMLMsg
        tCond.Level = "2"
        tCond.Index = "1"
        tCond.Code = "A1B"
        tCond.Name = "1-回音1"
        MsgLsit.Add(tCond)

        tCond = New XMLMsg
        tCond.Level = "1"
        tCond.Index = "1"
        tCond.Code = "A2"
        tCond.Name = "1-默认配置2"
        MsgLsit.Add(tCond)
        tCond = New XMLMsg
        tCond.Level = "2"
        tCond.Index = "0"
        tCond.Code = "A2A"
        tCond.Name = "1-声音2"
        MsgLsit.Add(tCond)
        tCond = New XMLMsg
        tCond.Level = "2"
        tCond.Index = "1"
        tCond.Code = "A2B"
        tCond.Name = "1-回音2"
        MsgLsit.Add(tCond)

        tCond = New XMLMsg
        tCond.Level = "0"
        tCond.Index = "1"
        tCond.Code = "B"
        tCond.Name = "方案2"
        MsgLsit.Add(tCond)
        tCond = New XMLMsg
        tCond.Level = "1"
        tCond.Index = "0"
        tCond.Code = "B1"
        tCond.Name = "2-默认配置1"
        MsgLsit.Add(tCond)
        tCond = New XMLMsg
        tCond.Level = "2"
        tCond.Index = "0"
        tCond.Code = "B1A"
        tCond.Name = "2-声音1"
        MsgLsit.Add(tCond)
        tCond = New XMLMsg
        tCond.Level = "2"
        tCond.Index = "1"
        tCond.Code = "B1B"
        tCond.Name = "2-回音1"
        MsgLsit.Add(tCond)

        tCond = New XMLMsg
        tCond.Level = "1"
        tCond.Index = "1"
        tCond.Code = "B2"
        tCond.Name = "2-默认配置2"
        MsgLsit.Add(tCond)
        tCond = New XMLMsg
        tCond.Level = "2"
        tCond.Index = "0"
        tCond.Code = "B2A"
        tCond.Name = "2-声音2"
        MsgLsit.Add(tCond)
        tCond = New XMLMsg
        tCond.Level = "2"
        tCond.Index = "1"
        tCond.Code = "B2B"
        tCond.Name = "2-回音2"
        MsgLsit.Add(tCond)

        ComboBox1.Items.Clear()
        Com1.Clear()
        Dim Comd1 = From x In MsgLsit Where x.Code = "A" Or x.Code = "B" Select x
        For Each t As XMLMsg In Comd1
            Com1.Add(t)
            ComboBox1.Items.Add(t.Name)
        Next
        If ComboBox1.Items.Count > 0 Then
            ComboBox1.SelectedIndex = 0
        End If

然后是二个SelectedIndexChanged事件
代码如下：

Private Sub ComboBox1_SelectedIndexChanged(sender As Object, e As EventArgs) Handles ComboBox1.SelectedIndexChanged
        If ComboBox1.SelectedIndex >= 0 Then
            Com2.Clear()
            ComboBox2.Items.Clear()
            Dim tCond As New XMLMsg
            tCond = Com1(ComboBox1.SelectedIndex)
            Dim Comd2 = From x In MsgLsit Where x.Level = 1 And x.Code.Substring(0, 1) = tCond.Code Select x
            For Each t As XMLMsg In Comd2
                Com2.Add(t)
                ComboBox2.Items.Add(t.Name)
            Next
            If ComboBox2.Items.Count > 0 Then
                ComboBox2.SelectedIndex = 0
            End If
        End If
    End Sub
    Private Sub ComboBox2_SelectedIndexChanged(sender As Object, e As EventArgs) Handles ComboBox2.SelectedIndexChanged
        If ComboBox2.SelectedIndex >= 0 Then
            Com3.Clear()
            ComboBox3.Items.Clear()
            Dim tCond As New XMLMsg
            tCond = Com2(ComboBox2.SelectedIndex)
            Dim Comd2 = From x In MsgLsit Where x.Level = 2 Select x
            For Each t As XMLMsg In Comd2
                If t.Code.Substring(0, 2) = tCond.Code Then
                    Com3.Add(t)
                    ComboBox3.Items.Add(t.Name)
                End If
            Next
            If ComboBox3.Items.Count > 0 Then
                ComboBox3.SelectedIndex = 0
            End If
        End If
    End Sub

效果如下图，你选择了方案2，只会出现方案2的内容，不会出现方案1的，我这里在代码上面，把都加了“1-”和“2”，这样可以把方案1和方案2的子项区分开。




最后说一句，VB.NET决对支持linq，VB.net 你做不到，是你没有用对，如果让你纠结，建议你早点换语言。