EPPlus - add filter

var columnFilters = new[]
{
	new {SheetName = "Sheet1", ColumnName = "FirstName", Values = new [] { "Bob", "John"}},
	new {SheetName = "Sheet1", ColumnName = "Age", Values = new [] { 30"}},
}.ToList();

//Apply filters
using (var pck = new ExcelPackage(new FileInfo(parametricsLogFilename)))
{
    columnFilters.ForEach(columnFilter =>
    {
        //Find the worksheet
        var worksheet = pck.Workbook.Worksheets.FirstOrDefault(sheet => sheet.Name.Equals(columnFilter.SheetName));
        if (worksheet == null) return;

        //Get the column names
        var columnInfos = worksheet
                            .Cells[worksheet.Dimension.Start.Row, worksheet.Dimension.Start.Column, 1, worksheet.Dimension.End.Column]
                            .Select((cell, index) => new
                            {
                                ColumnCell = cell,
                                Index = index
                            })
                            .ToList();

        //Find the column
        var columnInfo = columnInfos.FirstOrDefault(info => info.ColumnCell.Value.Equals(columnFilter.ColumnName));
        if (columnInfo == null) return;

        //Get reference to the worksheet xml for proper namespace
        var xdoc = worksheet.WorksheetXml;
        var nsm = new XmlNamespaceManager(xdoc.NameTable);
        nsm.AddNamespace("default", xdoc.DocumentElement.NamespaceURI);

        //Create the filters themselves
        var filterNodes = columnFilter.Values.Select(filterValue =>
        {
            var filterNode = xdoc.CreateNode(XmlNodeType.Element, "filter", xdoc.DocumentElement.NamespaceURI);
            var filterAtt = xdoc.CreateAttribute("val");
            filterAtt.Value = filterValue;
            filterNode.Attributes.Append(filterAtt);
            return filterNode;
        })
        .ToList();

        //Add filters to the collection
        var filtersNode = xdoc.CreateNode(XmlNodeType.Element, "filters", xdoc.DocumentElement.NamespaceURI);
        filterNodes.ForEach(filterNode =>
        {
            filtersNode.AppendChild(filterNode);
        });

        //Create the parent filter container
        var filterColumnNode = xdoc.CreateNode(XmlNodeType.Element, "filterColumn", xdoc.DocumentElement.NamespaceURI);
        var att = xdoc.CreateAttribute("colId");
        att.Value = $"{columnInfo.Index}";
        filterColumnNode.Attributes.Append(att);
        filterColumnNode.AppendChild(filtersNode);

        //Now add it to the autoFilters node
        var autoFilter = xdoc.SelectSingleNode("/default:worksheet/default:autoFilter", nsm);
        autoFilter.AppendChild(filterColumnNode);

        //Get a list of cells in the column. We can't just iterate over worksheet.Cells because if a column is completely blank, the IEnumerable is empty
        var rawCellsInColumn = (object[,])worksheet.Cells[worksheet.Dimension.Start.Row, columnInfo.Index + 1, worksheet.Dimension.End.Row, columnInfo.Index + 1].Value;
        var cellsInColumn = new List<(int RowNumber, object Value)>();
        for (int rowNumber = 0; rowNumber < rawCellsInColumn.GetLength(0); rowNumber++)
        {
            cellsInColumn.Add((rowNumber, rawCellsInColumn[rowNumber, 0]));
        }

        //Have to manually hide rows based on criteria
        var rowsToHide = cellsInColumn
            .Skip(1)
            .Where(cell => cell.Value == null || !columnFilter.Values.Contains(cell.Value))
            .ToList();

        rowsToHide
            .ForEach(cell => worksheet.Row(cell.RowNumber + 1).Hidden = true);
    });

    pck.Save();
}