IWorkbook workbook = new Workbook();
IWorksheet worksheet = workbook.Worksheets[0];

//Set data.
object[,] data = new object[,]{
    { "Preface",                                   "1",      1,  0 },
    { "Java SE5 and SE6",                          "1.1",    2,  1 },
    { "Java SE6",                                  "1.1.1",  2,  2 },
    { "The 4th edition",                           "1.2",    2,  1 },
    { "Changes",                                   "1.2.1",  3,  2 },
    { "Note on the cover design",                  "1.3",    4,  1 },
    { "Acknowledgements",                          "1.4",    4,  1 },
    { "Introduction",                              "2",      9,  0 },
    { "Prerequisites",                             "2.1",    9,  1 },
    { "Learning Java",                             "2.2",    10, 1 },
    { "Goals",                                     "2.3",    10, 1 },
    { "Teaching from this book",                   "2.4",    11, 1 },
    { "JDK HTML documentation",                    "2.5",    11, 1 },
    { "Exercises",                                 "2.6",    12, 1 },
    { "Foundations for Java",                      "2.7",    12, 1 },
    { "Source code",                               "2.8",    12, 1 },
    { "Coding standards",                          "2.8.1",  14, 2 },
    { "Errors",                                    "2.9",    14, 1 },
    { "Introduction to Objects",                   "3",      15, 0 },
    { "The progress of abstraction",               "3.1",    15, 1 },
    { "An object has an interface",                "3.2",    17, 1 },
    { "An object provides services",               "3.3",    18, 1 },
    { "The hidden implementation",                 "3.4",    19, 1 },
    { "Reusing the implementation",                "3.5",    20, 1 },
    { "Inheritance",                               "3.6",    21, 1 },
    { "Is-a vs. is-like-a relationships",          "3.6.1",  24, 2 },
    { "Interchangeable objects with polymorphism", "3.7",    25, 1 },
    { "The singly rooted hierarchy",               "3.8",    28, 1 },
    { "Containers",                                "3.9",    28, 1 },
    { "Parameterized types (Generics)",            "3.10",   29, 1 },
    { "Object creation & lifetime",                "3.11",   30, 1 },
    { "Exception handling: dealing with errors",   "3.12",   31, 1 },
    { "Concurrent programming",                    "3.13",   32, 1 },
    { "Java and the Internet",                     "3.14",   33, 1 },
    { "What is the Web?",                          "3.14.1", 33, 2 },
    { "Client-side programming",                   "3.14.2", 34, 2 },
    { "Server-side programming",                   "3.14.3", 38, 2 },
    { "Summary",                                   "3.15",   38, 1 }
};
worksheet.Range["A1:C38"].Value = data;

//Set ColumnWidth.
worksheet.Range["A:A"].ColumnWidthInPixel = 310;
worksheet.Range["B:C"].ColumnWidthInPixel = 150;

//Set IndentLevel.
for (int i = 0; i < data.GetLength(0); i++)
{
    worksheet.Range[i, 0].IndentLevel = (int)data[i, 3];
}

//Show the summary row above the detail rows.
worksheet.Outline.SummaryRow = SummaryRow.Above;

//Don't show the row outline when interacting with SJS, the exported excel file still show the row outline.
worksheet.ShowRowOutline = false;

//Set outline column.
worksheet.OutlineColumn.ColumnIndex = 0;
worksheet.OutlineColumn.ShowCheckBox = true;
worksheet.OutlineColumn.ShowImage = true;
worksheet.OutlineColumn.MaxLevel = 2;
worksheet.OutlineColumn.Images.Add(new ImageSource(File.Open("archiverFolder.png", FileMode.Open), ImageType.PNG));
worksheet.OutlineColumn.Images.Add(new ImageSource(File.Open("newFolder.png", FileMode.Open), ImageType.PNG));
worksheet.OutlineColumn.Images.Add(new ImageSource(File.Open("docFile.png", FileMode.Open), ImageType.PNG));
worksheet.OutlineColumn.CollapseIndicator = new ImageSource(File.Open("decreaseIndicator.png", FileMode.Open), ImageType.PNG);
worksheet.OutlineColumn.ExpandIndicator = new ImageSource(File.Open("increaseIndicator.png", FileMode.Open), ImageType.PNG);

worksheet.OutlineColumn.SetCheckStatus(0, true);
worksheet.OutlineColumn.SetCollapsed(1, true);

//Print the headings & gridlines.
worksheet.PageSetup.PrintHeadings = true;
worksheet.PageSetup.PrintGridlines = true;

//Save to json/excel/pdf.
workbook.ToJson(new FileStream("outlineColumn1.json", FileMode.Create));
workbook.Save("outlineColumn1.xlsx");
workbook.Save("outlineColumn1.pdf");