Export unbound DataGridView to CSV file

readme.md

Useful for quick and dirty utilities, otherwise a bound DataGridView with a BindList is best.

DataGridViewExtensions.cs

internal record RowRecord(DataGridViewRow Row, string RowItem);

public static class DataGridViewExtensions
{
    public static void ExportRows(this DataGridView sender, string fileName, string defaultNullValue = "(empty)")
    {

        File.WriteAllLines(fileName, sender.Rows.Cast<DataGridViewRow>()
            .Where(row => !row.IsNewRow)
            .Select(row => new RowRecord(
                row, string.Join(",", Array.ConvertAll(row.Cells.Cast<DataGridViewCell>()
                    .ToArray(), cell => (cell.Value == null) ? defaultNullValue : cell.Value.ToString()))
            ))
            .Select(@row => @row.RowItem));

    }
}

RowRecord.cs

internal record RowRecord(DataGridViewRow Row, string RowItem);