基于CSV文件数据为ListBox列表框添加拖拽操作的分类匹配限制

实现方案 #

我们只需要新增两个分类映射字典存储关联关系，再调整拖拽校验逻辑即可实现需求： #

1. 新增全局分类映射 #

在窗体类顶部新增两个私有字典，分别存储ListBox对应的分类、工具项对应的分类：

' 存储每个ListBox对应的分类编号
Private listBoxKategorie As New Dictionary(Of ListBox, Integer)
' 存储每个工具项对应的分类编号
Private werkzeugKategorie As New Dictionary(Of String, Integer)

2. 加载CSV时填充映射 #

在Form_Load事件中，读取CSV时同步填充两个映射字典：

• 读取CSV1（listboxpflege.csv）创建ListBox时，存入每个ListBox的分类编号（假设CSV1第五列<索引4>为分类值）
• 读取CSV2（Spritzguss.csv）加载工具项时，存入每个工具对应的分类编号（假设CSV2第二列<索引1>为分类值）

3. 调整拖拽校验逻辑 #

修改DragEnter事件实现拖拽时实时校验分类，不符合要求直接禁止拖拽：

Private Sub meineListbox_DragEnter(ByVal sender As System.Object, ByVal e As System.Windows.Forms.DragEventArgs)
    If e.Data.GetDataPresent(DataFormats.Text) Then
        Dim draggedTool = e.Data.GetData(DataFormats.Text).ToString()
        Dim targetListBox = CType(sender, ListBox)
        ' 校验拖拽项和目标列表分类是否一致
        If werkzeugKategorie.ContainsKey(draggedTool) AndAlso listBoxKategorie.ContainsKey(targetListBox) Then
            If werkzeugKategorie(draggedTool) = listBoxKategorie(targetListBox) Then
                e.Effect = DragDropEffects.Move
                Exit Sub
            End If
        End If
    End If
    e.Effect = DragDropEffects.None
End Sub

同时在DragDrop事件中增加二次校验，避免异常操作：

Private Sub meineListbox_DragDrop(ByVal sender As System.Object, ByVal e As System.Windows.Forms.DragEventArgs)
    Dim lbx As ListBox = CType(sender, ListBox)
    Dim draggedTool = e.Data.GetData(DataFormats.Text).ToString()
    ' 二次校验分类合法性
    If werkzeugKategorie(draggedTool) <> listBoxKategorie(lbx) Then
        MessageBox.Show("仅允许拖拽到同分类的列表中")
        Exit Sub
    End If
    If Not source Is Nothing Then
        source.Items.RemoveAt(sourceIndex)
    End If
    lbx.Items.Add(draggedTool)
End Sub

额外注意：原代码中MouseDown事件的If aIndex <= 0判断存在逻辑错误，会导致除第一个项外其他项无法触发拖拽，建议修改为If aIndex >= 0

完整修改后代码 #

Imports System.Windows.Forms
Imports System.IO

Public Class Form2
    Private meineListBoxen As New List(Of ListBox)
    ' 新增分类映射
    Private listBoxKategorie As New Dictionary(Of ListBox, Integer)
    Private werkzeugKategorie As New Dictionary(Of String, Integer)
    Private source As ListBox
    Private sourceIndex As Integer

    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles Me.Load
        Dim strZeilen() As String
        Dim strFelder() As String
        Dim strZeilen0() As String
        Dim strZeilen2() As String = IO.File.ReadAllLines("K:\Ruebel_Andreas\Modellpflege\Datenerfassung.csv")
        Dim strFelder1() As String
        strZeilen = File.ReadAllLines("K:\Ruebel_Andreas\Modellpflege\listboxpflege.csv")
        strZeilen0 = IO.File.ReadAllLines("K:\Ruebel_Andreas\Modellpflege\Spritzguss.csv")

        For i As Integer = 1 To strZeilen.GetUpperBound(0)
            strFelder = strZeilen(i).Split(";"c)
            Dim newListBox As New ListBox
            With newListBox
                .Left = CInt(strFelder(0))
                .Top = CInt(strFelder(1))
                .Width = CInt(strFelder(2))
                .Height = CInt(strFelder(3))
                .AllowDrop = True
            End With
            ' 存储ListBox对应分类
            listBoxKategorie.Add(newListBox, CInt(strFelder(4)))
            meineListBoxen.Add(newListBox)
            Me.Controls.Add(newListBox)
            AddHandler newListBox.MouseDown, AddressOf meineListbox_MouseDown
            AddHandler newListBox.DragDrop, AddressOf meineListbox_DragDrop
            AddHandler newListBox.DragEnter, AddressOf meineListbox_DragEnter
        Next

        ' 加载工具项并存储工具分类
        For a As Integer = 0 To strZeilen0.GetUpperBound(0)
            Dim toolArr = strZeilen0(a).Split(";"c)
            Dim toolName = toolArr(0)
            Dim toolCate = CInt(toolArr(1))
            werkzeugKategorie(toolName) = toolCate
            Me.meineListBoxen(0).Items.Add(toolName)
        Next

        For j As Integer = 1 To strZeilen2.GetUpperBound(0)
            strFelder1 = strZeilen2(j).Split(" "c)
            With meineListBoxen(j)
                .Items.Add(strFelder1(4))
            End With
            For Each itm In meineListBoxen(j).Items
                If meineListBoxen(0).Items.Contains(itm) Then meineListBoxen(0).Items.Remove(itm)
            Next
        Next
    End Sub

    Private Sub Form1_MouseMove(sender As Object, e As MouseEventArgs) Handles Me.MouseMove
        Me.lblMaus.Text = "X: " & e.X & " , Y:" & e.Y
    End Sub

    Private Sub meineListbox_MouseDown(ByVal sendre As System.Object, ByVal e As System.Windows.Forms.MouseEventArgs)
        Dim aPoint As Point
        Dim lbx As ListBox
        Dim aIndex As Integer

        lbx = CType(sendre, ListBox)
        aPoint = New Point(e.X, e.Y)
        aIndex = lbx.IndexFromPoint(aPoint)
        Try
            ' 修复原逻辑错误，索引>=0才是有效选中项
            If aIndex >= 0 Then
                source = lbx
                sourceIndex = aIndex
                lbx.DoDragDrop(lbx.Items(aIndex), DragDropEffects.All)
            End If
        Catch ex As Exception
            MessageBox.Show("Bitte wählen Sie ein Werkzeug aus")
        End Try
    End Sub

    Private Sub meineListbox_DragDrop(ByVal sender As System.Object, ByVal e As System.Windows.Forms.DragEventArgs)
        Dim lbx As ListBox = CType(sender, ListBox)
        Dim draggedTool = e.Data.GetData(DataFormats.Text).ToString()
        ' 二次校验分类
        If werkzeugKategorie(draggedTool) <> listBoxKategorie(lbx) Then
            MessageBox.Show("仅允许拖拽到同分类的列表中")
            Exit Sub
        End If
        If Not source Is Nothing Then
            source.Items.RemoveAt(sourceIndex)
        End If
        lbx.Items.Add(draggedTool)
    End Sub

    Private Sub meineListbox_DragEnter(ByVal sender As System.Object, ByVal e As System.Windows.Forms.DragEventArgs)
        If e.Data.GetDataPresent(DataFormats.Text) Then
            Dim draggedTool = e.Data.GetData(DataFormats.Text).ToString()
            Dim targetListBox = CType(sender, ListBox)
            If werkzeugKategorie.ContainsKey(draggedTool) AndAlso listBoxKategorie.ContainsKey(targetListBox) Then
                If werkzeugKategorie(draggedTool) = listBoxKategorie(targetListBox) Then
                    e.Effect = DragDropEffects.Move
                    Exit Sub
                End If
            End If
        End If
        e.Effect = DragDropEffects.None
    End Sub

    Private Sub cmdSave_Click(ByVal sender As Object, ByVal e As EventArgs) Handles Speichern.Click
        Dim w As New IO.StreamWriter("K:\Ruebel_Andreas\Modellpflege\Datenerfassung.csv")
        For i = 0 To meineListBoxen.Count - 1
            w.WriteLine(meineListBoxen.Item(i))
        Next
        w.Close()
    End Sub

    Private Sub WerkzeugHinzufügen_Click(sender As Object, e As EventArgs) Handles WerkzeugHinzufügen.Click
        Process.Start("K:\Ruebel_Andreas\Modellpflege\Spritzguss.csv")
    End Sub

    Private Sub StellplatzHinzufügen_Click(sender As Object, e As EventArgs) Handles StellplatzHinzufügen.Click
        Process.Start("K:\Ruebel_Andreas\Modellpflege\listboxpflege.csv")
    End Sub
End Class

内容的提问来源于stack exchange，提问作者erin karakaş