VBA: How to update a trendline label in excel

Question

sometimes it happens that the trendline label in excel isn't updated when I changed the graph-data. Therefore I want to update via VBA. I want to do it for all existing trendlines in all sheets and charts.

My code until now doesn't work. You will find the error in the comment.

    Sub Auto_Open()
        Debug.Print "Start"
        Dim oChart As ChartObject, nSheet As Integer, nChart As Integer
        nSheet = 1
        Do While nSheet <= Sheets.Count
            nChart = 1
            Do While nChart <= Sheets(nSheet).ChartObjects.Count
                nSeriesCollection = 1
                'Debug.Print Sheets(nSheet).ChartObjects(nChart).SeriesCollection.Count
                'Error in next line
                Do While nSeriesCollection <= Sheets(nSheet).ChartObjects(nChart).SeriesCollection.Count
                    Debug.Print "nSheet: " & nSheet & " nChart: " & nChart
                    Set oChart = Sheets(nSheet).ChartObjects(nChart)
                    oChart.Activate
                    'Next line has to changed too
                    ActiveChart.SeriesCollection(1).Trendlines(1).Select
                    With Selection
                        .DisplayRSquared = False
                        .DisplayEquation = False
                        .DisplayRSquared = True
                        .DisplayEquation = True
                    End With            
                    nSeriesColletion = nSeriesColletion + 1
                Loop
                nChart = nChart + 1
            Loop
            nSheet = nSheet + 1
        Loop
    End Sub 

########################################################################

There is a run-time error '438'. Object doesn't support this property or method in the line with the error comment.

Answer 1

Here is the solution: :)

Sub Auto_Open()
    Debug.Print "###########################################"
    Debug.Print "Start"
    Dim oChart As ChartObject, nSheet As Integer, nChart As Integer
    nSheet = 1
    Do While nSheet <= Sheets.Count
        Debug.Print "Sheet: " & nSheet
        nChart = 1
        Do While nChart <= Sheets(nSheet).ChartObjects.Count
            Debug.Print " ChartObjects: " & nChart
            nSeriesCollection = 1
            Do While nSeriesCollection <= Sheets(nSheet).ChartObjects(nChart).Chart.SeriesCollection.Count
                Debug.Print "  SeriesCollection: " & nSeriesCollection

                Sheets(nSheet).ChartObjects(nChart).Chart.SeriesCollection(nSeriesCollection).Trendlines(1).DisplayEquation = True

                nSeriesCollection = nSeriesCollection + 1
            Loop
            nChart = nChart + 1
        Loop
        nSheet = nSheet + 1
    Loop
End Sub