Help with viewing definition of acronym when placing mouse on a row of a listbox

Public Class Form1
    Private lastHoveredIndex As Integer = -1

    Private Sub OnLoad(sender As Object, e As EventArgs) Handles MyBase.Load
        ListBox1.DataSource = (From i In Enumerable.Range(0, 20) Select New Acronym() With {.ID = i, .Acronym = String.Format("ACR{0}", i), .Definition = String.Format("Definition for ACR{0}", i)}).ToList()
        ListBox1.DisplayMember = "Acronym"
    End Sub

    Private Sub OnMouseMove(sender As Object, e As MouseEventArgs) Handles ListBox1.MouseMove
        Dim newHoveredIndex = ListBox1.IndexFromPoint(e.Location)
        If (lastHoveredIndex <> newHoveredIndex) Then
            lastHoveredIndex = newHoveredIndex
            If (lastHoveredIndex > -1) Then
                ToolTip1.Active = False
                ToolTip1.SetToolTip(ListBox1, CType(ListBox1.Items(lastHoveredIndex), Acronym).Definition)
                ToolTip1.Active = True
            End If
        End If
    End Sub
End Class

Class Acronym
    Public Property ID() As Integer
    Public Property Acronym() As String
    Public Property Definition() As String
End Class

Select allOpen in new window

<Global.Microsoft.VisualBasic.CompilerServices.DesignerGenerated()> _
Partial Class Form1
    Inherits System.Windows.Forms.Form

    'Form overrides dispose to clean up the component list.
    <System.Diagnostics.DebuggerNonUserCode()> _
    Protected Overrides Sub Dispose(ByVal disposing As Boolean)
        Try
            If disposing AndAlso components IsNot Nothing Then
                components.Dispose()
            End If
        Finally
            MyBase.Dispose(disposing)
        End Try
    End Sub

    'Required by the Windows Form Designer
    Private components As System.ComponentModel.IContainer

    'NOTE: The following procedure is required by the Windows Form Designer
    'It can be modified using the Windows Form Designer.  
    'Do not modify it using the code editor.
    <System.Diagnostics.DebuggerStepThrough()> _
    Private Sub InitializeComponent()
        Me.components = New System.ComponentModel.Container()
        Me.ListBox1 = New System.Windows.Forms.ListBox()
        Me.ToolTip1 = New System.Windows.Forms.ToolTip(Me.components)
        Me.SuspendLayout()
        '
        'ListBox1
        '
        Me.ListBox1.FormattingEnabled = True
        Me.ListBox1.Location = New System.Drawing.Point(13, 13)
        Me.ListBox1.Name = "ListBox1"
        Me.ListBox1.Size = New System.Drawing.Size(259, 238)
        Me.ListBox1.TabIndex = 0
        '
        'Form1
        '
        Me.AutoScaleDimensions = New System.Drawing.SizeF(6.0!, 13.0!)
        Me.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font
        Me.ClientSize = New System.Drawing.Size(284, 261)
        Me.Controls.Add(Me.ListBox1)
        Me.Name = "Form1"
        Me.Text = "Form1"
        Me.ResumeLayout(False)

    End Sub

    Friend WithEvents ListBox1 As ListBox
    Friend WithEvents ToolTip1 As ToolTip
End Class

Select allOpen in new window

    Private Sub OnLoad(sender As Object, e As EventArgs) Handles MyBase.Load
        ListBox1.DataSource = (From i In Enumerable.Range(0, 20) Select New Acronym() With {.ID = i, .Acronym = String.Format("ACR{0}", i), .Definition = String.Format("Definition for ACR{0}", i)}).ToList()
        ListBox1.DisplayMember = "Acronym"
    End Sub

Select allOpen in new window

Class Acronym
    Public Property ID() As Integer
    Public Property Acronym() As String
    Public Property Definition() As String
End Class

Select allOpen in new window