vb.net图例标记大小

Question

在名为ChartSmile的表单中，我想增加图例中标记的大小。这段代码没有做任何事情，我错过了什么？

Public Event CustomizeLegend As EventHandler(Of CustomizeLegendEventArgs)

Private Sub ChartSmile_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        AddHandler CustomizeLegend, AddressOf Chart1_CustomizeLegend
End Sub

Private Sub Chart1_CustomizeLegend(sender As Object, _
                               e As CustomizeLegendEventArgs) Handles Me.CustomizeLegend
    For Each item In e.LegendItems
        item.MarkerSize = 50
    Next
End Sub