C# Excel Chart Change color

I am trying to change the line color of the chart series to None. I tried setting the color and the marker property but the program errors out.

My code:

 Excel.ChartObjects _ChartObjects = (Excel.ChartObjects)(oSheet1.ChartObjects(Missing.Value));
            Excel.ChartObject _ChartObject = _ChartObjects.Add(170, 0, 400, 300);
            Excel.Chart _Chart = _ChartObject.Chart;
            Excel.Range oRng1;
            oRng1 = oSheet1.get_Range("A1","E55");            
            _Chart.SetSourceData(oRng1, Excel.XlRowCol.xlColumns);
            _Chart.ChartType = Microsoft.Office.Interop.Excel.XlChartType.xlLineMarkers;
            oWB.ShowPivotChartActiveFields = true;
            //_Chart.ChartTitle.Font.Size = 12;
            _Chart.SetElement(Microsoft.Office.Core.MsoChartElementType.msoElementDataTableWithLegendKeys);
            _Ch开发者_StackOverflowart.DataTable.Font.Size = 6;
            oWB.ShowPivotChartActiveFields = false;
            _Chart.SetElement(Microsoft.Office.Core.MsoChartElementType.msoElementPrimaryValueAxisTitleRotated);
            _Chart.SetElement(Microsoft.Office.Core.MsoChartElementType.msoElementLegendNone);
            //_Chart.Legend.Delete();
            _Chart.SetElement(Microsoft.Office.Core.MsoChartElementType.msoElementPrimaryValueAxisTitleNone);
            _Chart.Location(Excel.XlChartLocation.xlLocationAsNewSheet, "Tax Weekly Term-Chart");
           Excel.SeriesCollection seriesCollection = (Excel.SeriesCollection)_Chart.SeriesCollection(Type.Missing);

            Excel.Series series = (Excel.Series)seriesCollection.Item(4);

Need code to set the color of the series to None.Any suggestions would be useful.

This code can set the colours of the slices of all the pie charts in my spreadsheet based on each slice's legend's label:

Sub SetPieChartColours()

    ' Iterates through all pie charts in the dashboard and apply colours to the appropriate legends

    ' Colour indices:
    ' Passed (Green)             10
    ' Not Completed (Yellow)     19
    ' No run (Blue)              37
    ' Failed (Maroon)            18
    ' Failed Issue (Pink)        24
    ' Failed Defect (Red)        3

    Dim savePtLabel As String
    Dim ThisPt As String

    Dim NumPoints As Integer
    Dim x As Integer

    Dim pie As ChartObject
    For Each pie In ActiveSheet.ChartObjects

         ' Check that the current chart object is a pie chart
         If pie.Chart.ChartType = xlPie Then

            NumPoints = pie.Chart.SeriesCollection(1).Points.Count
            For x = 1 To NumPoints

                ' Save the label currently attached to the current slice
                If pie.Chart.SeriesCollection(1).Points(x).HasDataLabel = True Then
                    savePtLabel = pie.Chart.SeriesCollection(1).Points(x).DataLabel.Text
                Else
                    savePtLabel = ""
                End If

                ' Assign a new data label of just the point name
                pie.Chart.SeriesCollection(1).Points(x).ApplyDataLabels Type:= _
                   xlDataLabelsShowLabel, AutoText:=True
                ThisPt = pie.Chart.SeriesCollection(1).Points(x).DataLabel.Text

                ' Based on the label of this slice, set the color
                Select Case ThisPt
                    Case "Failed-Defect"
                        pie.Chart.SeriesCollection(1).Points(x).Interior.ColorIndex = 3
                    Case "Failed-Issue"
                        pie.Chart.SeriesCollection(1).Points(x).Interior.ColorIndex = 24
                    Case "Failed"
                        pie.Chart.SeriesCollection(1).Points(x).Interior.ColorIndex = 18
                    Case "No Run"
                        pie.Chart.SeriesCollection(1).Points(x).Interior.ColorIndex = 37
                    Case "Not Completed"
                        pie.Chart.SeriesCollection(1).Points(x).Interior.ColorIndex = 18
                    Case "Passed"
                        pie.Chart.SeriesCollection(1).Points(x).Interior.ColorIndex = 10
                    Case Else
                        ' Aroo! The label of the current slice doesn't match any expected labels
                        pie.Chart.SeriesCollection(1).Points(x).Interior.ColorIndex = 1
                End Select

                ' Return the label to it's original state
                pie.Chart.SeriesCollection(1).Points(x).ApplyDataLabels Type:=xlDataLabelsShowNone, AutoText:=True

            Next x
         End If
     Next

End Sub

And this code can set barchart colours:

Sub SetBarChartColours()

    Dim savePtLabel As String
    Dim ThisPt As String

    Dim NumPoints As Integer
    Dim x As Integer

    Dim bar As ChartObject

    For Each bar In ActiveSheet.ChartObjects
       If bar.Chart.Name = "Dashboard Chart 5" Then
            NumPoints = bar.Chart.SeriesCollection.Count
            For x = 1 To NumPoints
                MsgBox bar.Chart.Legend.LegendEntries(x).LegendKey.Interior.ColorIndex


            Next x
        End If
    Next

End Sub

Maybe could help you!