public LineStyle Style {get; set;}

var workbook = Workbook.Create("test.xlsx" )

// Get the first worksheet. A workbook contains at least 1 worksheet.
var cellWorksheet = workbook.Worksheets[ 0 ];

// Set cell content and Border styles.
cellWorksheet.Cells[ "C5" ].Value = "Bottom";
cellWorksheet.Cells[ "C5" ].Style.Borders[ BorderType.Bottom ].Style = LineStyle.Double;
cellWorksheet.Cells[ "C5" ].Style.Borders[ BorderType.Bottom ].Color = Color.Red;

cellWorksheet.Cells[ "C8" ].Value = "Top";
cellWorksheet.Cells[ "C8" ].Style.Borders[ BorderType.Top ].Style = LineStyle.DashDot;

cellWorksheet.Cells[ "C11" ].Value = "Right";
cellWorksheet.Cells[ "C11" ].Style.Borders[ BorderType.Right ] = new Border() { Style = LineStyle.MediumDashed, Color = Color.Green };

// Save workbook to disk.
workbook.Save();