title: Setting Font.Bold and Column.Width for Cells in OPEN XML
body: <p>I've been using OPEN XML to create a spread sheet which can then be downloaded. I want to set the column widths and also change the header to bold. I've done this using Office.Interop.Excel but I'm struggling with this format. My code is below, you can see I've set up a font but have been unable to assign it to my spread sheet, I have got messages saying it's not possible to assign to a tree.</p>
  
  <pre><code>        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&lt;WorksheetPart&gt;();
              worksheetPart.Worksheet = new DocumentFormat.OpenXml.Spreadsheet.Worksheet(new SheetData());
  
              DocumentFormat.OpenXml.Spreadsheet.Sheets sheets = spreadsheetDocument.WorkbookPart.Workbook.AppendChild&lt;DocumentFormat.OpenXml.Spreadsheet.Sheets&gt;(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();
          }
  </code></pre>