I want to draw a Line in a .xlsx file using a C# program. The line should be able to go from a starting-point to a lower placed point, that is to the left side of the starting point.

Example: from E5 (5/5) to C10 (3/10).

I already did the following code, but every time I open the file, it tells me that a problem occurred and if they should recreate as much as possible. If I press no, nothing happens and if yes its a line from (3/5) to (5/10).

I created the code using the OpenXml v2.19 nuget package (my company uses this):

using DocumentFormat.OpenXml;
using DocumentFormat.OpenXml.Packaging;
using DocumentFormat.OpenXml.Spreadsheet;
using D = DocumentFormat.OpenXml.Drawing;
using DocumentFormat.OpenXml.Drawing.Spreadsheet;
using DS = DocumentFormat.OpenXml.Drawing.Spreadsheet;
using System;

public class ExcelLinie
{
    static void Main()
    {
        string desktopPath = Environment.GetFolderPath(Environment.SpecialFolder.Desktop);
        string filePath = System.IO.Path.Combine(desktopPath, "Example.xlsx");

        using (SpreadsheetDocument document = SpreadsheetDocument.Create(filePath, SpreadsheetDocumentType.Workbook))
        {
            // Create Workbook-Part
            WorkbookPart workbookPart = document.AddWorkbookPart();
            workbookPart.Workbook = new Workbook();

            // Add Worksheet
            WorksheetPart worksheetPart = workbookPart.AddNewPart<WorksheetPart>();
            worksheetPart.Worksheet = new Worksheet(new SheetData());

            // Add Sheets in workbook
            Sheets sheets = document.WorkbookPart.Workbook.AppendChild(new Sheets());

            // New Sheet
            Sheet sheet = new Sheet()
            {
                Id = document.WorkbookPart.GetIdOfPart(worksheetPart),
                SheetId = 1,
                Name = "MySheet"
            };
            sheets.Append(sheet);

            // Add Drawing
            DrawingsPart drawingsPart;

            if (worksheetPart.DrawingsPart == null)
            {
                drawingsPart = worksheetPart.AddNewPart<DrawingsPart>();
                worksheetPart.Worksheet.AppendChild(new Drawing() { Id = worksheetPart.GetIdOfPart(drawingsPart) });
            }
            else
            {
                drawingsPart = worksheetPart.DrawingsPart;
            }

            // Creates XML structure
            var worksheetDrawing = new WorksheetDrawing();

            // Creates Line
            var twoCellAnchor = new TwoCellAnchor(
                new DS.FromMarker( // Start point
                    new ColumnId("5"),
                    new ColumnOffset("0"),
                    new RowId("5"),
                    new RowOffset("0")
                ),
                new DS.ToMarker( // End point
                    new ColumnId("3"),
                    new ColumnOffset("0"),
                    new RowId("10"),
                    new RowOffset("0")
                ),
                new ConnectionShape(
                    new NonVisualConnectionShapeProperties(
                        new NonVisualDrawingProperties() { Id = (UInt32Value)3U, Name = "Straight Connector 2" },
                        new NonVisualConnectorShapeDrawingProperties()
                    ), // Shape
                    new ShapeProperties(
                        new D.Transform2D(
                            new D.Offset() { X = 0, Y = 0 },
                            new D.Extents() { Cx = 0, Cy = 0 }
                        ),
                        new D.PresetGeometry(
                            new D.AdjustValueList()
                        )
                        { Preset = D.ShapeTypeValues.Line },
                        new D.Outline(
                            new D.SolidFill(
                                new D.RgbColorModelHex() { Val = "326417" } // Color Hexcode
                            )
                        )
                        {
                            Width = 12700 * 2 // Thickness 1 Point = 12700 EMUs
                        }
                    )
                ),
                new ClientData()
            );
            worksheetDrawing.Append(twoCellAnchor);

            drawingsPart.WorksheetDrawing = worksheetDrawing;
            drawingsPart.WorksheetDrawing.Save();

            // Save Workbook
            workbookPart.Workbook.Save();
        }

        Console.WriteLine($"File saved at {filePath}");
    }
}