设置OPEN XML中单元格的粗体和列宽

我一直在使用OPEN XML创建一个可以下载的电子表格。我想设置列宽，并将标题更改为粗体。我已经使用Office.Interop.Excel完成了这项工作，但我对这种格式感到很吃力。我的代码在下面，你可以看到我已经设置了一个字体，但无法将其分配给我的电子表格，我收到消息说无法分配给树。

        SpreadsheetDocument spreadsheetDocument = SpreadsheetDocument.Create(fileName, SpreadsheetDocumentType.Workbook);    //Open(fileName, true);
        try
        {
            WorkbookPart workbookpart = spreadsheetDocument.AddWorkbookPart();
            workbookpart.Workbook = new DocumentFormat.OpenXml.Spreadsheet.Workbook();
            WorksheetPart worksheetPart = workbookpart.AddNewPart<WorksheetPart>();
            worksheetPart.Worksheet = new DocumentFormat.OpenXml.Spreadsheet.Worksheet(new SheetData());
            DocumentFormat.OpenXml.Spreadsheet.Sheets sheets = spreadsheetDocument.WorkbookPart.Workbook.AppendChild<DocumentFormat.OpenXml.Spreadsheet.Sheets>(new DocumentFormat.OpenXml.Spreadsheet.Sheets());
            Sheet sheet = new Sheet() { Id = spreadsheetDocument.WorkbookPart.GetIdOfPart(worksheetPart), SheetId = 1, Name = "Models" };
            sheets.Append(sheet);
            DocumentFormat.OpenXml.Spreadsheet.Font boldFont = new DocumentFormat.OpenXml.Spreadsheet.Font();
            Bold bFontBold = new Bold();
            boldFont.Append(bFontBold);
            DocumentFormat.OpenXml.Spreadsheet.Worksheet worksheet = new DocumentFormat.OpenXml.Spreadsheet.Worksheet();
            SheetData sheetData = new SheetData();
 ........
                Row row = new Row();
                Cell cell = new Cell()
                {
                    CellReference = "A" + (intI + 1),
                    DataType = CellValues.String,
                    CellValue = new CellValue(ModelBookrowDetail[0])
                };
                row.Append(cell);
                Cell cell2 = new Cell()
                {
                    CellReference = "B" + (intI + 1),
                    DataType = CellValues.String,
                    CellValue = new CellValue(ModelBookrowDetail[1])
                };
                row.Append(cell2);
 .........
                sheetData.Append(row);
            }
            worksheet.Append(sheetData);
            worksheetPart.Worksheet = worksheet;
            spreadsheetDocument.Close();
        }
        catch
        {
            spreadsheetDocument.Close();
        }