Here is the working code. This is a prototype. For a larger number of changes, one might open the document only once. Also, there are some hard-coded things like sheet name and cell type that would have to be parameterized before this can be called production-ready.
http://openxmldeveloper.org/forums/4005/ShowThread.aspx was very helpful.
using System;
using System.Collections.Generic;
using System.Data;
using System.Linq;
using System.Text;
using DocumentFormat.OpenXml;
using DocumentFormat.OpenXml.Packaging;
using DocumentFormat.OpenXml.Spreadsheet;
using System.Xml;
using System.IO;
using System.Diagnostics;
namespace OpenXMLWindowsApp
{
public class OpenXMLWindowsApp
{
public void UpdateSheet()
{
UpdateCell("Chart.xlsx", "20", 2, "B");
UpdateCell("Chart.xlsx", "80", 3, "B");
UpdateCell("Chart.xlsx", "80", 2, "C");
UpdateCell("Chart.xlsx", "20", 3, "C");
ProcessStartInfo startInfo = new ProcessStartInfo("Chart.xlsx");
startInfo.WindowStyle = ProcessWindowStyle.Normal;
Process.Start(startInfo);
}
public static void UpdateCell(string docName, string text,
uint rowIndex, string columnName)
{
// Open the document for editing.
using (SpreadsheetDocument spreadSheet =
SpreadsheetDocument.Open(docName, true))
{
WorksheetPart worksheetPart =
GetWorksheetPartByName(spreadSheet, "Sheet1");
if (worksheetPart != null)
{
Cell cell = GetCell(worksheetPart.Worksheet,
columnName, rowIndex);
cell.CellValue = new CellValue(text);
cell.DataType =
new EnumValue<CellValues>(CellValues.Number);
// Save the worksheet.
worksheetPart.Worksheet.Save();
}
}
}
private static WorksheetPart
GetWorksheetPartByName(SpreadsheetDocument document,
string sheetName)
{
IEnumerable<Sheet> sheets =
document.WorkbookPart.Workbook.GetFirstChild<Sheets>().
Elements<Sheet>().Where(s => s.Name == sheetName);
if (sheets.Count() == 0)
{
// The specified worksheet does not exist.
return null;
}
string relationshipId = sheets.First().Id.Value;
WorksheetPart worksheetPart = (WorksheetPart)
document.WorkbookPart.GetPartById(relationshipId);
return worksheetPart;
}
// Given a worksheet, a column name, and a row index,
// gets the cell at the specified column and
private static Cell GetCell(Worksheet worksheet,
string columnName, uint rowIndex)
{
Row row = GetRow(worksheet, rowIndex);
if (row == null)
return null;
return row.Elements<Cell>().Where(c => string.Compare
(c.CellReference.Value, columnName +
rowIndex, true) == 0).First();
}
// Given a worksheet and a row index, return the row.
private static Row GetRow(Worksheet worksheet, uint rowIndex)
{
return worksheet.GetFirstChild<SheetData>().
Elements<Row>().Where(r => r.RowIndex == rowIndex).First();
}
}
}
