How to change Excel chart series color in C#, VB.NET?

using Syncfusion.XlsIO;

Imports Syncfusion.XlsIO

using (ExcelEngine excelEngine = new ExcelEngine())
{
    //Instantiate the application object
    IApplication application = excelEngine.Excel;
 
    //Add a workbook
    IWorkbook workbook = application.Workbooks.Create(1);
 
    //The first worksheet object in the worksheets collection is accessed
    IWorksheet worksheet = workbook.Worksheets[0];
    worksheet.Name = "First Chart";
 
    //Entering the chart data
    worksheet.Range["A1"].Text = "Texas books Unit sales";
    worksheet.Range["A1:D1"].Merge();
    worksheet.Range["A1"].CellStyle.Font.Bold = true;
 
    worksheet.Range["B2"].Text = "Jan";
    worksheet.Range["C2"].Text = "Feb";
    worksheet.Range["D2"].Text = "Mar";
 
    worksheet.Range["A3"].Text = "Austin";
    worksheet.Range["A4"].Text = "Dallas";
    worksheet.Range["A5"].Text = "Houston";
    worksheet.Range["A6"].Text = "San Antonio";
 
    worksheet.Range["B3"].Number = 53.75;
    worksheet.Range["B4"].Number = 52.85;
    worksheet.Range["B5"].Number = 59.77;
    worksheet.Range["B6"].Number = 96.15;
 
    worksheet.Range["C3"].Number = 79.79;
    worksheet.Range["C4"].Number = 59.22;
    worksheet.Range["C5"].Number = 10.09;
    worksheet.Range["C6"].Number = 73.02;
 
    worksheet.Range["D3"].Number = 26.72;
    worksheet.Range["D4"].Number = 33.71;
    worksheet.Range["D5"].Number = 45.81;
    worksheet.Range["D6"].Number = 12.17;
 
    //Adding a New (Embedded chart) to the worksheet 
    IChartShape shape = worksheet.Charts.Add();
    shape.ChartType = ExcelChartType.Column_Clustered;
    shape.DataRange = worksheet.Range["B3:D6"];
    shape.IsSeriesInRows = false;
    shape.PrimaryCategoryAxis.Title = "City";
    shape.PrimaryCategoryAxis.CategoryLabels = worksheet["A3:A6"];
    shape.PrimaryValueAxis.Title = "Sales (in Dollars)";
    shape.ChartTitle = "Texas Books Unit Sales";
    shape.HasDataTable = true;
 
    //Setting the serie names
    IChartSerie serieOne = shape.Series[0];
    serieOne.Name = "Jan";
    IChartSerie serietwo = shape.Series[1];
    serietwo.Name = "Feb";
    IChartSerie seriethree = shape.Series[2];
    seriethree.Name = "March";
 
    //Changing the series color
    serietwo.DataPoints.DefaultDataPoint.DataFormat.AreaProperties.ForegroundColorIndex = ExcelKnownColors.Red;
                
    //Save the file
    workbook.SaveAs("Output.xlsx");
 
    System.Diagnostics.Process.Start("Output.xlsx");}

Using excelEngine As ExcelEngine = New ExcelEngine()
    'Instantiate the application object
    Dim application As IApplication = excelEngine.Excel
 
    'Add a workbook
    Dim workbook As IWorkbook = application.Workbooks.Create(1)
 
    'The first worksheet object in the worksheets collection is accessed
    Dim worksheet As IWorksheet = workbook.Worksheets(0)
    worksheet.Name = "First Chart"
 
    'Entering the chart data
    worksheet.Range("A1").Text = "Texas books Unit sales"
    worksheet.Range("A1:D1").Merge()
    worksheet.Range("A1").CellStyle.Font.Bold = True
 
    worksheet.Range("B2").Text = "Jan"
    worksheet.Range("C2").Text = "Feb"
    worksheet.Range("D2").Text = "Mar"
 
    worksheet.Range("A3").Text = "Austin"
    worksheet.Range("A4").Text = "Dallas"
    worksheet.Range("A5").Text = "Houston"
    worksheet.Range("A6").Text = "San Antonio"
 
    worksheet.Range("B3").Number = 53.75
    worksheet.Range("B4").Number = 52.85
    worksheet.Range("B5").Number = 59.77
    worksheet.Range("B6").Number = 96.15
 
    worksheet.Range("C3").Number = 79.79
    worksheet.Range("C4").Number = 59.22
    worksheet.Range("C5").Number = 10.09
    worksheet.Range("C6").Number = 73.02
 
    worksheet.Range("D3").Number = 26.72
    worksheet.Range("D4").Number = 33.71
    worksheet.Range("D5").Number = 45.81
    worksheet.Range("D6").Number = 12.17
 
    'Adding a New (Embedded chart) to the Worksheet 
    Dim shape As IChartShape = worksheet.Charts.Add()
    shape.ChartType = ExcelChartType.Column_Clustered
    shape.DataRange = worksheet.Range("B3:D6")
    shape.IsSeriesInRows = False
    shape.PrimaryCategoryAxis.Title = "City"
    shape.PrimaryCategoryAxis.CategoryLabels = worksheet("A3:A6")
    shape.PrimaryValueAxis.Title = "Sales (in Dollars)"
    shape.ChartTitle = "Texas Books Unit Sales"
    shape.HasDataTable = True
 
    'Setting the serie names
    Dim serieOne As IChartSerie = shape.Series(0)
    serieOne.Name = "Jan"
    Dim serietwo As IChartSerie = shape.Series(1)
    serietwo.Name = "Feb"
    Dim seriethree As IChartSerie = shape.Series(2)
    seriethree.Name = "March"
 
    'Changing the series color
    serietwo.DataPoints.DefaultDataPoint.DataFormat.AreaProperties.ForegroundColorIndex = ExcelKnownColors.Red
 
    'Save the file
    workbook.SaveAs("Output.xlsx")
 
    System.Diagnostics.Process.Start("Output.xlsx")
End Using