.NET (Core and Framework)

Imports OWC11 = Microsoft.Office.Interop.Owc11

    Public Class Form1
Private m_Chart As OWC11.ChChart

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

        m_Chart = AxChartSpace1.Charts.Add
        Dim oSer As OWC11.ChSeries = m_Chart.SeriesCollection.Add
        Dim aCats As Object() = New Object() {"A", "B", "C"}
        Dim aVals As Object() = New Object() {100, 120, 128}
        oSer.SetData(OWC11.ChartDimensionsEnum.chDimSeriesNames, -1, "MySeries")
        oSer.SetData(OWC11.ChartDimensionsEnum.chDimCategories, -1, aCats)
        oSer.SetData(OWC11.ChartDimensionsEnum.chDimValues, -1, aVals)
    End Sub

Private Sub AxChartSpace1_ClickEvent(ByVal sender As Object, ByVal _
   e As System.EventArgs) _
   Handles AxChartSpace1.ClickEvent

     Debug.WriteLine(Now & " click")

     Dim mousePoint As Point = AxChartSpace1.PointToClient(MousePosition)

     Dim oSer As OWC11.ChSeries = m_Chart.SeriesCollection(0)
     Dim i As Integer
     For i = 0 To oSer.Points.Count - 1

         Dim le = oSer.Points(i).Left
         Dim ri = oSer.Points(i).Right
         Dim hi = oSer.Points(i).Top
         Dim lo = oSer.Points(i).Bottom

         If mousePoint.X > le And mousePoint.X < ri Then
             m_Chart.SeriesCollection(0).Points(i).Interior.Color = RGB(100, 100, 100)
         Else
             m_Chart.SeriesCollection(0).Points(i).Interior.Color = RGB(0, 0, 200)
         End If

     Next

 End Sub