How to create an xls file with NPOI?

Question

All I want to do is to create a file with 1 line and few columns to make some test.

However I cannot find a simple way to do such a thing. Most help I found seem to also use a database.

I found one that doesn't.

Trying to create a new .xlsx file using NPOI and write to it

However it seems like a little too much for such a simple task. Is there a tool which would allow me to do something as simple as

Create file
file.cell[0,0] = ...

Answer 1

You could use the EPPlus package. Find it on NuGet.

string fileName = @"C:\test\MyNewExcelFile.xlsx";
FileInfo newFile = new FileInfo(fileName);
using (ExcelPackage xlPackage = new ExcelPackage(newFile)) // create the xlsx file
{
    // Add a new worksheet on which to put data 
    ExcelWorksheet xlWorksheet = xlPackage.Workbook.Worksheets.Add("Test");
    // Write data to cell(s)
    xlWorksheet.Cells["A1"] = ...
    // Write the file
    xlPackage.Save();
}

EDIT

Modification to replace worksheet if it already exists.

const string fileName = @"C:\test\MyNewExcelFile.xlsx";
const string sheetName = @"test";

FileInfo newFile = new FileInfo(fileName);

using (ExcelPackage xlPackage = new ExcelPackage(newFile)) // create the xlsx file
{
    // if sheet already exists, delete it
    // use LINQ to query collection of worksheets
    ExcelWorksheet xlWorksheet = xlPackage.Workbook.Worksheets.SingleOrDefault(ws => ws.Name == sheetName);
    if (xlWorksheet != null)
    {
        // worksheet exists - delete it
        xlPackage.Workbook.Worksheets.Delete(sheetName);
    }
    // Add new worksheet on which to put data 
    ExcelWorksheet xlWorksheet = xlPackage.Workbook.Worksheets.Add("Test");
    // Write data to cell(s)
    xlWorksheet.Cells["A1"] = ...
    // Write the file
    xlPackage.Save();
}