Add Excel chart data labels with formula in C#, VB.NET using XlsIO

using Syncfusion.XlsIO;

Imports Syncfusion.XlsIO

//Create an instance of ExcelEngine
using (ExcelEngine excelEngine = new ExcelEngine())
{
    //Instantiate the application object
    IApplication application = excelEngine.Excel;
    application.DefaultVersion = ExcelVersion.Excel2016;
 
    //Create a workbook
    IWorkbook workbook = application.Workbooks.Create(1);
    IWorksheet sheet = workbook.Worksheets[0];
 
    //Enter values to the cells from A1 to C6
    sheet.Range["A1"].Text = "Month";
    sheet.Range["B1"].Text = "Product A";
    sheet.Range["C1"].Text = "Product B";
 
    sheet.Range["A2"].Text = "Jan";
    sheet.Range["A3"].Text = "Feb";
    sheet.Range["A4"].Text = "Mar";
    sheet.Range["A5"].Text = "Apr";
    sheet.Range["A6"].Text = "May";
 
    sheet.Range["B2"].Number = 111;
    sheet.Range["B3"].Number = 361;
    sheet.Range["B4"].Number = 336;
    sheet.Range["B5"].Number = 40;
    sheet.Range["B6"].Number = 219;
 
    sheet.Range["C2"].Number = 182;
    sheet.Range["C3"].Number = 283;
    sheet.Range["C4"].Number = 406;
    sheet.Range["C5"].Number = 449;
    sheet.Range["C6"].Number = 337;
 
    //Create a chart
    IChartShape chart = sheet.Charts.Add();
    chart.ChartType = ExcelChartType.Line;
    chart.DataRange = sheet.Range["A1:C6"];
 
    //Set formula as data label text
    chart.Series[0].DataPoints[0].DataLabels.IsFormula = true;
    chart.Series[0].DataPoints[0].DataLabels.Text = "='Sheet1'!$A$2";
 
    //Save the workbook
    workbook.SaveAs("Output.xlsx");
    workbook.Close();
}

'Create an instance of ExcelEngine
Using excelEngine As ExcelEngine = New ExcelEngine()
 
    'Instantiate the application object
    Dim application As IApplication = excelEngine.Excel
    application.DefaultVersion = ExcelVersion.Excel2016
 
    'Create a workbook
    Dim workbook As IWorkbook = application.Workbooks.Create(1)
    Dim sheet As IWorksheet = workbook.Worksheets(0)
 
    'Enter values to the cells from A1 to C6
    sheet.Range("A1").Text = "Month"
    sheet.Range("B1").Text = "Product A"
    sheet.Range("C1").Text = "Product B"
 
    sheet.Range("A2").Text = "Jan"
    sheet.Range("A3").Text = "Feb"
    sheet.Range("A4").Text = "Mar"
    sheet.Range("A5").Text = "Apr"
    sheet.Range("A6").Text = "May"
 
    sheet.Range("B2").Number = 111
    sheet.Range("B3").Number = 361
    sheet.Range("B4").Number = 336
    sheet.Range("B5").Number = 40
    sheet.Range("B6").Number = 219
 
    sheet.Range("C2").Number = 182
    sheet.Range("C3").Number = 283
    sheet.Range("C4").Number = 406
    sheet.Range("C5").Number = 449
    sheet.Range("C6").Number = 337
 
    'Create a chart
    Dim chart As IChartShape = sheet.Charts.Add()
    chart.ChartType = ExcelChartType.Line
    chart.DataRange = sheet.Range("A1:C6")
 
    'Set formula as data label text
    chart.Series(0).DataPoints(0).DataLabels.IsFormula = True
    chart.Series(0).DataPoints(0).DataLabels.Text = "='Sheet1'!$A$2"
 
    'Save the workbook
    workbook.SaveAs("Output.xlsx")
    workbook.Close()
End Using