Export grid to Excel, Pdf and txt (csv)

@{
    var grid = "LunchGrid";
}
@(Html.Awe().Grid(grid)
        .Url(Url.Action("GetItems"))
        .Mod(o => o.ColumnsSelector())
        .Persistence(Persistence.Session)
        .Resizable()
        .Height(350)
        .Columns(
        new Column { Bind = "Id", Width = 80 },
        new Column { Bind = "Person" },
        new Column { Bind = "Food.Name" },
        new Column { Bind = "Date", Width = 150 },
        new Column { Bind = "Price", ClientFormatFunc = "priceFormat", Width = 110 },
        new Column { Bind = "Country.Name", Header = "Country" },
        new Column { Bind = "Chef.FirstName,Chef.LastName", Prop = "ChefName", Header = "Chef" },
        new Column { Bind = "Location" }))

<br />
<div class="bar">
    <button id="exportGrid" type="button" class="awe-btn">Export grid to excel</button>
    <button id="exportGridPdf" type="button" class="awe-btn">Export grid to Pdf</button>
    <button id="exportGridTxt" type="button" class="awe-btn">Export grid to txt (csv)</button>
    <div style="padding: 0 1em; display: inline-block;">
        <label>@Html.Awe().CheckBox("allPages") All pages</label>
    </div>

    <br />
    <br />
    <button id="exportAll" type="button" class="awe-btn">Export all records to excel</button>
</div>
<script>
    $(function() {
        $('#exportAll').click(function() {
            getFile('@Url.Action("ExportAllToExcel", "GridExportToExcelDemo")');
        });

        $('#exportGrid').click(function() {
            getFile('@Url.Action("ExportGridToExcel", "GridExportToExcelDemo")');
        });

        $('#exportGridPdf').click(function() {
            getFile('@Url.Action("ExportGridToPdf", "GridExportToExcelDemo")');
        });

        $('#exportGridTxt').click(function() {
            getFile('@Url.Action("ExportGridToTxt", "GridExportToExcelDemo")');
        });

        function getFile(url) {
            var $form = $('<form method="post"/>').attr('action', url).appendTo('body');

            var grid = $('#@(grid)');

            // request parameters (sorting, grouping, any parent parameters)
            var req = grid.data('api').getRequest();

            // send visible columns info, binds to GridExpParams
            var viscols = aweUtils.getVisCols(grid);
            awef.loop(viscols,
                function(v) {
                    $form.append("<input type='hidden' name='visNames' value='" + v + "'/>");
                });

            awef.loop(req,
                function(val) {
                    $form.append("<input type='hidden' name='" + val.name + "' value='" + val.value + "'/>");
                });

            $form.append($('#allPages').clone());
            $form.submit();
            $form.remove();
        }
    });

    function priceFormat(lunch, prop) {
        var price = lunch[prop];
        return price + ' USD';
    }
</script>

public class GridExportToExcelDemoController : Controller
{
    public IActionResult Index()
    {
        return View();
    }

    public IActionResult GetItems(GridParams g)
    {
        return Json((BuildGridModel(g)).ToDto());
    }

    private GridModel<Lunch> BuildGridModel(GridParams g)
    {
        var query = Db.Lunches.AsQueryable();

        var gmb = new GridModelBuilder<Lunch>(query, g)
        {
            KeyProp = o => o.Id,
            Map = o => new
            {
                o.Id,
                o.Person,
                FoodName = o.Food.Name,
                o.Location,
                o.Price,
                Date = o.Date.ToShortDateString(),
                CountryName = o.Country.Name,
                ChefName = o.Chef.FullName
            },
            MakeFooter = info =>
                {
                    if (info.Level == 0)
                    {
                        return new
                        {
                            Id = "Total",
                            Price = "Min: " + info.Items.Min(o => o.Price),
                            Date = "Max: " + info.Items.Max(o => o.Date).ToShortDateString()
                        };
                    }

                    return new
                    {
                        Price = "Min: " + info.Items.Min(o => o.Price),
                        Date = "Max: " + info.Items.Max(o => o.Date).ToShortDateString()
                    };
                }
        };

        return gmb.BuildModel();
    }

    private ExpColumn[] getExpColumns()
    {
        var expColumns = new[]
        {
            new ExpColumn { Name = "Id", Width = 1.5f },
            new ExpColumn { Name = "Person", Width = 2.5f },
            new ExpColumn { Name = "Food", Width = 3 },
            new ExpColumn { Name = "Date", Width = 2.2f },
            new ExpColumn
            {
                Name = "Price",
                Width = 2, 
                // if you don't specify ClientFormatFunc the builder (xls/pdf/txt) will use model[Name] to get the cell value
                ClientFormatFunc = (lunch, property) =>
                {
                    var value = lunch.GetType().GetProperty("Price")?.GetValue(lunch).ToString();
                    if (!string.IsNullOrEmpty(value))
                    {
                        value += " USD";
                    }

                    return value;
                }
            },
            new ExpColumn { Name = "CountryName", Width = 3, Header = "Country" },
            new ExpColumn { Name = "ChefName", Width = 3.2f, Header = "Chef" },
            new ExpColumn { Name = "Location", Width = 2.7f }
        };

        return expColumns;
    }

    [HttpPost]
    public IActionResult ExportGridToExcel(GridParams g, GridExpParams expParams, bool? allPages)
    {
        if (allPages.HasValue && allPages.Value)
        {
            g.Paging = false;
        }

        var gridModel = BuildGridModel(g);

        var workbook = new GridExcelBuilder(getExpColumns())
        {
            // adding ExpParams so the hidden columns won't get exported
            ExpParams = expParams
        }.Build(gridModel);

        using (var stream = new MemoryStream())
        {
            workbook.Write(stream);
            stream.Close();
            return File(stream.ToArray(), "application/vnd.ms-excel", "lunches.xls");
        }
    }

    [HttpPost]
    public IActionResult ExportGridToTxt(GridParams g, GridExpParams expParams, bool? allPages)
    {
        if (allPages.HasValue && allPages.Value)
        {
            g.Paging = false;
        }

        var gridModel = BuildGridModel(g);

        var res = new GridTxtBuilder(getExpColumns())
        {
            // adding ExpParams so the hidden columns won't get exported
            ExpParams = expParams
        }.Build(gridModel);

        using (var memoryStream = new MemoryStream())
        {
            using (var writer = new StreamWriter(memoryStream))
            {
                writer.WriteLine(res);
            }

            return File(memoryStream.ToArray(), "text/plain", "lunches.txt");
        }
    }

    [HttpPost]
    public IActionResult ExportGridToPdf(GridParams g, GridExpParams expParams, bool? allPages)
    {
        if (allPages.HasValue && allPages.Value)
        {
            g.Paging = false;
        }

        var gridModel = BuildGridModel(g);

        var builder = new GridPdfBuilder(getExpColumns())
        {
            // adding ExpParams so the hidden columns won't get exported
            ExpParams = expParams
        };

        var workStream = new MemoryStream();
        var writer = new PdfWriter(workStream);
        var pdf = new PdfDocument(writer);
        var document = new Document(pdf);

        document.Add(new Paragraph("Hello World!"));
        document.Add(new Paragraph("Export to pdf example (using iText7)"));
        document.Add(new Paragraph(new Text("\n")));

        var table = builder.Build(gridModel);
        document.Add(table);
        writer.SetCloseStream(false);
        document.Close();

        var byteInfo = workStream.ToArray();
        workStream.Write(byteInfo, 0, byteInfo.Length);
        workStream.Position = 0;

        return File(workStream, "application/pdf", "lunches.pdf");
    }

    /// <summary>
    /// Demonstrates the simplest way of creating an excel workbook 
    /// it exports all the lunches records, without taking into account any sorting/paging that is done on the client side
    /// </summary>
    /// <returns></returns>
    [HttpPost]
    public IActionResult ExportAllToExcel()
    {
        var workbook = new HSSFWorkbook();
        var sheet = workbook.CreateSheet("sheet1");

        var res = Db.Lunches.ToArray();

        var items = res.Select(
            o => new
            {
                o.Id,
                o.Person,
                FoodName = o.Food.Name,
                o.Location,
                CountryName = o.Country.Name,
                ChefName = o.Chef.FullName
            }).ToList();

        var properties = new[] { "Id", "Person", "FoodName", "CountryName", "ChefName", "Location" };
        var headers = new[] { "Id", "Person", "Food", "Country", "Chef", "Location" };

        var headerRow = sheet.CreateRow(0);

        // create header
        for (int i = 0; i < properties.Length; i++)
        {
            var cell = headerRow.CreateCell(i);
            cell.SetCellValue(headers[i]);
        }

        // fill content 
        for (int i = 0; i < items.Count; i++)
        {
            var rowIndex = i + 1;
            var row = sheet.CreateRow(rowIndex);

            for (int j = 0; j < properties.Length; j++)
            {
                var cell = row.CreateCell(j);
                var o = items[i];
                cell.SetCellValue(o.GetType().GetProperty(properties[j]).GetValue(o, null).ToString());
            }
        }

        using (var stream = new MemoryStream())
        {
            workbook.Write(stream);
            stream.Close();
            return File(stream.ToArray(), "application/vnd.ms-excel", "lunches.xls");
        }
    }
}