如何将独立ListBox的数据与另一ListBox绑定实现选项关联

你的需求是让食物列表和卡路里列表的对应项永久关联，选中食物时自动匹配对应卡路里，无需手动选择第二个列表，实现方式如下：

实现效果参考 #

方案1：同步选中索引（轻量改动） #

因为你添加食物和卡路里的时候是按顺序成对添加的，同下标位置的项本身就是对应关系，只需要同步两个ListBox的选中索引即可实现绑定。

Public Class Form1
    Public strfood As String

    Private Sub btnAdd_Click(sender As Object, e As EventArgs) Handles btnAdd.Click
        Dim calory As Single
        strfood = InputBox("Enter food item", "Food List")
        calory = InputBox("Enter calory", "Calory List")
        FoodList.Items.Add(strfood)
        CaloryList.Items.Add(calory)
    End Sub

    ' 新增食物列表选中变化事件，同步卡路里列表的选中项
    Private Sub FoodList_SelectedIndexChanged(sender As Object, e As EventArgs) Handles FoodList.SelectedIndexChanged
        ' 加判断避免索引越界报错
        If FoodList.SelectedIndex >= 0 AndAlso FoodList.SelectedIndex < CaloryList.Items.Count Then
            CaloryList.SelectedIndex = FoodList.SelectedIndex
        End If
    End Sub

    Private Sub btnDisplay_Click(sender As Object, e As EventArgs) Handles btnDisplay.Click
        ' 优化：直接用索引取值，即使卡路里列表没选中也能拿到对应值，更稳妥
        If FoodList.SelectedIndex >= 0 Then
            Dim selecteditem As String = FoodList.SelectedItem.ToString
            Dim selectedcalory As String = CaloryList.Items(FoodList.SelectedIndex).ToString
            MessageBox.Show("Food :" & selecteditem & " " & "Calories :" & selectedcalory)
        End If
    End Sub
End Class

方案2：数据源绑定（更规范，不易出错） #

如果想从数据层面直接关联，避免后续手动同步索引的麻烦，可以用结构化数据源绑定，两个列表绑定同一个数据源，选中会自动同步：

' 先定义食物结构类
Public Class FoodItem
    Public Property Name As String
    Public Property Calory As Single
End Class

Public Class Form1
    ' 定义统一的食物数据源
    Dim foodDataSource As New List(Of FoodItem)

    Private Sub btnAdd_Click(sender As Object, e As EventArgs) Handles btnAdd.Click
        Dim foodName = InputBox("Enter food item", "Food List")
        Dim caloryVal = Val(InputBox("Enter calory", "Calory List"))
        foodDataSource.Add(New FoodItem With {.Name = foodName, .Calory = caloryVal})
        ' 刷新两个列表的绑定
        FoodList.DataSource = Nothing
        FoodList.DataSource = foodDataSource
        FoodList.DisplayMember = "Name"
        CaloryList.DataSource = Nothing
        CaloryList.DataSource = foodDataSource
        CaloryList.DisplayMember = "Calory"
    End Sub

    Private Sub btnDisplay_Click(sender As Object, e As EventArgs) Handles btnDisplay.Click
        If FoodList.SelectedItem IsNot Nothing Then
            Dim selectedFood = CType(FoodList.SelectedItem, FoodItem)
            MessageBox.Show($"Food :{selectedFood.Name} Calories :{selectedFood.Calory}")
        End If
    End Sub
End Class

内容的提问来源于stack exchange，提问作者3llyas