Excel Chart formatting in C# and VB.NET

using System;
using GemBox.Spreadsheet;
using GemBox.Spreadsheet.Charts;
using GemBox.Spreadsheet.Drawing;

class Program
{
    static void Main()
    {
        // If using the Professional version, put your serial key below.
        SpreadsheetInfo.SetLicense("FREE-LIMITED-KEY");

        var workbook = new ExcelFile();
        var worksheet = workbook.Worksheets.Add("Chart");

        // Add data which will be used by the Excel chart.
        worksheet.Cells["A1"].Value = "Month";
        worksheet.Cells["A2"].Value = "January";
        worksheet.Cells["A3"].Value = "February";
        worksheet.Cells["A4"].Value = "March";
        worksheet.Cells["A5"].Value = "April";
        worksheet.Cells["A6"].Value = "May";
        worksheet.Cells["A7"].Value = "June";
        worksheet.Cells["A8"].Value = "July";
        worksheet.Cells["A9"].Value = "August";
        worksheet.Cells["A10"].Value = "September";
        worksheet.Cells["A11"].Value = "October";
        worksheet.Cells["A12"].Value = "November";
        worksheet.Cells["A13"].Value = "December";

        // Fill the values.
        worksheet.Cells["B1"].Value = "Sales";
        var random = new Random();

        for (int i = 1; i <= 12; i++)
            worksheet.Cells[i, 1].SetValue(random.Next(2000, 5000));

        // Set header row and formatting.
        worksheet.Rows[0].Style.Font.Weight = ExcelFont.BoldWeight;
        worksheet.Columns[0].SetWidth(3, LengthUnit.Centimeter);
        worksheet.Columns[1].Style.NumberFormat = "\"$\"#,##0";

        // Make entire sheet print on a single page.
        worksheet.PrintOptions.FitWorksheetWidthToPages = 1;
        worksheet.PrintOptions.FitWorksheetHeightToPages = 1;

        // Create Excel chart and select data for it.
        var chart = worksheet.Charts.Add<LineChart>("D2", "P25");
        chart.SelectData(worksheet.Cells.GetSubrangeAbsolute(0, 0, 12, 1), true);

        // Define colors.
        var backgroundColor = DrawingColor.FromName(%BackgroundColor%);
        var seriesColor = DrawingColor.FromName(%SeriesColor%);
        var textColor = DrawingColor.FromName(%TextColor%);
        var borderColor = DrawingColor.FromName(DrawingColorName.Black);

        // Format chart.
        chart.Fill.SetSolid(backgroundColor);

        var outline = chart.Outline;
        outline.Width = Length.From(2, LengthUnit.Point);
        outline.Fill.SetSolid(borderColor);

        // Format plot area.
        chart.PlotArea.Fill.SetSolid(DrawingColor.FromName(DrawingColorName.White));

        outline = chart.PlotArea.Outline;
        outline.Width = Length.From(1.5, LengthUnit.Point);
        outline.Fill.SetSolid(borderColor);

        // Format chart title.
        var textFormat = chart.Title.TextFormat;
        textFormat.Size = Length.From(20, LengthUnit.Point);
        textFormat.Font = "Arial";
        textFormat.Fill.SetSolid(textColor);

        // Format vertical axis.
        textFormat = chart.Axes.Vertical.TextFormat;
        textFormat.Fill.SetSolid(textColor);
        textFormat.Italic = true;

        // Format horizontal axis.
        textFormat = chart.Axes.Horizontal.TextFormat;
        textFormat.Fill.SetSolid(textColor);
        textFormat.Size = Length.From(12, LengthUnit.Point);
        textFormat.Bold = true;

        // Format vertical major gridlines.
        chart.Axes.Vertical.MajorGridlines.Outline.Width = Length.From(0.5, LengthUnit.Point);

        // Format series.
        var series = chart.Series[0];
        outline = series.Outline;
        outline.Width = Length.From(3, LengthUnit.Point);
        outline.Fill.SetSolid(seriesColor);

        // Format series markers.
        series.Marker.MarkerType = MarkerType.Circle;
        series.Marker.Size = 10;
        series.Marker.Fill.SetSolid(textColor);
        series.Marker.Outline.Fill.SetSolid(seriesColor);

        workbook.Save("Chart Formatting.%OutputFileType%");
    }
}