Referencing Excel cell and range in C# and VB.NET

using GemBox.Spreadsheet;

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

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

        // Referencing cells from sheet using cell names and indexes.
        worksheet.Cells["A1"].Value = "Cell A1.";
        worksheet.Cells[1, 0].Value = "Cell in 2nd row and 1st column [A2].";

        // Referencing cells from row using cell names and indexes.
        worksheet.Rows["4"].Cells["B"].Value = "Cell in row 4 and column B [B4].";
        worksheet.Rows[4].Cells[1].Value = "Cell in 5th row and 2nd column [B5].";

        // Referencing cells from column using cell names and indexes.
        worksheet.Columns["C"].Cells["7"].Value = "Cell in column C and row 7 [C7].";
        worksheet.Columns[2].Cells[7].Value = "Cell in 3rd column and 8th row [C8].";

        // Referencing cell range using A1 notation [G2:N12].
        var range = worksheet.Cells.GetSubrange("G2:N12");
        range[0].Value = $"From {range.StartPosition} to {range.EndPosition}";
        range[1, 0].Value = $"From ({range.FirstRowIndex},{range.FirstColumnIndex}) to ({range.LastRowIndex},{range.LastColumnIndex})";
        range.Style.Borders.SetBorders(MultipleBorders.Outside,
            SpreadsheetColor.FromName(ColorName.Red),
            LineStyle.Thick);

        // Referencing cell range using absolute position [I5:M11].
        range = range.GetSubrangeAbsolute(4, 8, 10, 12);
        range[0].Value = $"From {range.StartPosition} to {range.EndPosition}";
        range[1, 0].Value = $"From ({range.FirstRowIndex},{range.FirstColumnIndex}) to ({range.LastRowIndex},{range.LastColumnIndex})";
        range.Style.Borders.SetBorders(MultipleBorders.Outside,
            SpreadsheetColor.FromName(ColorName.Green),
            LineStyle.Medium);

        // Referencing cell range using relative position [K8:L10].
        range = range.GetSubrangeRelative(3, 2, 2, 2);
        range[0].Value = $"From {range.StartPosition} to {range.EndPosition}";
        range[1, 0].Value = $"From ({range.FirstRowIndex},{range.FirstColumnIndex}) to ({range.LastRowIndex},{range.LastColumnIndex})";
        range.Style.Borders.SetBorders(MultipleBorders.Outside,
            SpreadsheetColor.FromName(ColorName.Blue),
            LineStyle.Thin);

        workbook.Save("Cell Referencing.%OutputFileType%");
    }
}