is it possible to edit .xlsm files using NPOI with C#

Question

Thanks for the help from people on this site, I was able to modify .xlsx file using NPOI. Code is below, but my final goal is to be able to modify .xlsm file cell value. Is there a way to do this? I tried to run with the following code but after won't be able to open the file once i ran the program.

XSSFWorkbook templateWorkbook;
using (FileStream fs = new FileStream(@"C:\Users\jzhu\Desktop\FlexTimeSheetTest.xlsm", FileMode.Open, FileAccess.ReadWrite))
{
    templateWorkbook = new XSSFWorkbook(fs);
    fs.Close();
}

XSSFSheet sheet = (XSSFSheet)templateWorkbook.GetSheet("Sheet1");
sheet.GetRow(0).GetCell(0).SetCellValue("Drago");
sheet.ForceFormulaRecalculation = true;

File.Delete(@"C:\Users\jzhu\Desktop\FlexTimeSheetTest.xlsm");

using (FileStream file = new FileStream(@"C:\Users\jzhu\Desktop\FlexTimeSheetTest.xlsm", FileMode.CreateNew, FileAccess.Write))
{
    templateWorkbook.Write(file);
    file.Close();
}

Answer 1

Update your NPOI library to latest version (2.1.3.1 at present time).

Using this version, your code and sample xlsm file with one macro recorded - I got valid file after modifying it by your code.

Excel is able to open it, and macro can be run.

Answer 2

            XSSFWorkbook xlWorkbook;

            using (FileStream file = new FileStream(toEditFile,FileMode.Open, FileAccess.Read))
            {
                xlWorkbook = new XSSFWorkbook(file);
            }

            var xlWorksheet = xlWorkbook.GetSheet(@"sheet");
            // do stuff
            
            using (FileStream file = new FileStream(toEditFile, FileMode.Create, FileAccess.Write))
            {
                xlWorkbook.Write(file);
                file.Close();
            }