VB - Graphs (Series being added)

Question

I have two separate graphs but every time I go back to a different graph. It adds the series again which causes it to break. I've tried adding the series to the Series Collection but then says it cannot find them.

 Private Sub Finances_Load(sender As Object, e As EventArgs) Handles MyBase.Load
    ChrPriceChange.ChartAreas("ChartArea").AxisX.ScrollBar.Enabled = True
    ChrPriceChange.ChartAreas("ChartArea").AxisX.IsLabelAutoFit = True
    ChrPriceChange.ChartAreas("ChartArea").AxisX.ScaleView.Size = 4
    ChrRoomProfit.ChartAreas("ChartArea").AxisX.ScrollBar.Enabled = True
    ChrRoomProfit.ChartAreas("ChartArea").AxisX.IsLabelAutoFit = True
    ChrRoomProfit.ChartAreas("ChartArea").AxisX.ScaleView.Size = 6
End Sub

Private Sub CmbType_SelectedIndexChanged(sender As Object, e As EventArgs) Handles CmbType.SelectedIndexChanged
    If CmbType.SelectedItem = "Price Change" Then

        ChrPriceChange.Series.Add("Single Room")
        ChrPriceChange.Series.Add("Double Room")
        ChrPriceChange.Series.Add("Family Room")
        ChrPriceChange.Series.Add("per Adult")
        ChrPriceChange.Series.Add("per Child")
        ChrPriceChange.Visible = True
        ChrRoomProfit.Visible = False

        MyConn.ConnectionString = dataFile
        MyConn.Open()
        Dim cmd As OleDbCommand = New OleDbCommand("SELECT * FROM [Prices] ORDER BY `Last Modified` ASC", MyConn)
        Dim dr As OleDbDataReader = cmd.ExecuteReader
        While dr.Read
            ChrPriceChange.Series("Single Room").Points.AddXY(dr("Last Modified").ToString, dr("Single").ToString)
            If (ChrPriceChange.ChartAreas(0).AxisX.Maximum > ChrPriceChange.ChartAreas(0).AxisX.ScaleView.Size) Then
                ChrPriceChange.ChartAreas(0).AxisX.ScaleView.Scroll(ChrPriceChange.ChartAreas(0).AxisX.Maximum)
            End If
            ChrPriceChange.Series("Double Room").Points.AddXY(dr("Last Modified").ToString, dr("Double").ToString)
            ChrPriceChange.Series("Family Room").Points.AddXY(dr("Last Modified").ToString, dr("Family").ToString)
            ChrPriceChange.Series("per Adult").Points.AddXY(dr("Last Modified").ToString, dr("Adult").ToString)
            ChrPriceChange.Series("per Child").Points.AddXY(dr("Last Modified").ToString, dr("Child").ToString)
        End While
        MyConn.Close()
        cmd.Dispose()
    End If

    If CmbType.SelectedItem = "Room Profit" Then
        ChrRoomProfit.Series.Add("Total Made")

        ChrRoomProfit.Visible = True
        ChrPriceChange.Visible = False

        MyConn.ConnectionString = dataFile
        MyConn.Open()
        Dim cmd As OleDbCommand = New OleDbCommand("SELECT * FROM [BookingInformation] ORDER BY `Date In` ASC", MyConn)
        Dim dr As OleDbDataReader = cmd.ExecuteReader
        While dr.Read
            ChrRoomProfit.Series("Total Made").Points.AddXY(dr("Date In").ToString, dr("Total").ToString)

            If (ChrRoomProfit.ChartAreas(0).AxisX.Maximum > ChrRoomProfit.ChartAreas(0).AxisX.ScaleView.Size) Then
                ChrRoomProfit.ChartAreas(0).AxisX.ScaleView.Scroll(ChrRoomProfit.ChartAreas(0).AxisX.Maximum)
            End If
        End While
        MyConn.Close()
        cmd.Dispose()
    End If
End Sub

Answer 1

Realised it was because I didn't have anything to clear it. ChrPriceChange.Series.Clear