Question

Is it possible to create a plot from List(Of Decimal) values in Excel with VB? I would like to avoid dumping data directly into a table, then creating the chart from that. Here is what I have so far, but I am getting a data type mismatch when I try to assign .XValues and .Values to the list. Is there some sort of conversion that needs to happen to turn a list into a series?

    Dim Series As Excel.Series
    Dim xVals As New List(Of Decimal)(New Decimal() {1, 3, 4, 5})
    Dim yVals As New List(Of Decimal)(New Decimal() {2, 2, 2, 2})
    xlWorkSheet = CType(Globals.ThisAddIn.Application.Worksheets.Add(), Excel.Worksheet)

    xlWorkSheet.Activate()
    xlWorkSheet.Name = "My Sheet"
    xlCharts = xlWorkSheet.ChartObjects
    xlChartObj = xlCharts.Add(150, 30, 400, 250)
    xlChart = xlChartObj.Chart

    With xlChart
        .ChartType = Excel.XlChartType.xlXYScatterLines
        .HasLegend = True
        .Legend.Position = Excel.XlLegendPosition.xlLegendPositionRight
        .HasTitle = True
        .ChartTitle.Text = "Test Chart"
        For i = 0 To channels.Count - 1
            .SeriesCollection.NewSeries()
            Series = .SeriesCollection(i + 1)
            Series.XValues = xVals
            Series.Values = yvals
        Next
        .Location(Excel.XlChartLocation.xlLocationAsNewSheet)
    End With

UPDATE:

I seems like the following code will work, but it is not very ideal. Is there a better way to do this other than converting the array to a string representation of the array like I did?

    Dim Series As Excel.Series
    Dim xVals As New List(Of Decimal)(New Decimal() {1, 3, 4, 5})
    Dim yVals As New List(Of Decimal)(New Decimal() {2, 2, 2, 2})
    Dim xString As String
    Dim yString As String
    xlWorkSheet = CType(Globals.ThisAddIn.Application.Worksheets.Add(), Excel.Worksheet)

    xlWorkSheet.Activate()
    xlWorkSheet.Name = "My Sheet"
    xlCharts = xlWorkSheet.ChartObjects
    xlChartObj = xlCharts.Add(150, 30, 400, 250)
    xlChart = xlChartObj.Chart

    With xlChart
        .ChartType = Excel.XlChartType.xlXYScatterLines
        .HasLegend = True
        .Legend.Position = Excel.XlLegendPosition.xlLegendPositionRight
        .HasTitle = True
        .ChartTitle.Text = "Test Chart"
        For i = 0 To channels.Count - 1
            .SeriesCollection.NewSeries()
            Series = .SeriesCollection(i + 1)

            xString = "={"
            xString += xVals(0).ToString
            For k = 1 To xVals.Count - 1
                xString += ","
                xString += xVals(k).ToString
            Next
            xString = "}"

            yString = "={"
            yString += yVals(0).ToString
            For k = 1 To yVals.Count - 1
                yString += ","
                yString += yVals(k).ToString
            Next
            yString = "}"

            Series.XValues = xString
            Series.Values = yString
        Next
        .Location(Excel.XlChartLocation.xlLocationAsNewSheet)
    End With

Answer 1

I was able to get what I wanted with the following code using Ranges stored as objects. The string method I mentioned in my second block of code had a limit of 8000+ characters (not sure of actual number, 8192?).

Dim Series As Excel.Series
Dim xVals As New List(Of Decimal)(New Decimal() {1, 3, 4, 5})
Dim yVals As New List(Of Decimal)(New Decimal() {2, 2, 2, 2})
Dim xRange As Object
Dim yRange As Object
Dim tempSheet as Excel.Worksheet

xlWorkSheet = CType(Globals.ThisAddIn.Application.Worksheets.Add(), Excel.Worksheet)
xlWorkSheet.Activate()
xlWorkSheet.Name = "My Sheet"
xlCharts = xlWorkSheet.ChartObjects
xlChartObj = xlCharts.Add(150, 30, 400, 250)
xlChart = xlChartObj.Chart

With xlChart
    .ChartType = Excel.XlChartType.xlXYScatterLines
    .HasLegend = True
    .Legend.Position = Excel.XlLegendPosition.xlLegendPositionRight
    .HasTitle = True
    .ChartTitle.Text = "Test Chart"
    For i = 0 To channels.Count - 1
        tempSheet = CType(Globals.ThisAddIn.Application.Worksheets.Add(), Excel.Worksheet)
        tempSheet.Activate()
        With tempSheet
            .Visible = False
            For k = 0 To xVals.Count - 1
                tempSheet.Cells(k + 1, 1).Value = xVals(k)
                tempSheet.Cells(k + 1, 2).Value = yVals(k) 'Assumes yVals.Count = xVals.Count
            Next
            xRange = tempSheet.Range("A1:A" + xVals.Count.ToString).Value
            yRange = tempSheet.Range("B1:B" + xVals.Count.ToString).Value
            Globals.ThisAddIn.Application.DisplayAlerts = False
            .Delete()
            Globals.ThisAddIn.Application.DisplayAlerts = True
        End With

        Series = .SeriesCollection.NewSeries()
        With Series
            .XValues = xRange
            .Values = yRange
        End With            
    Next
    .Location(Excel.XlChartLocation.xlLocationAsNewSheet)
End With