[HttpGet]
public ViewResult Index()
{
    return View(CreateExportableGrid());
}

[HttpGet]
public ViewResult ExportIndex()
{
    return Export(CreateExportableGrid(), "People");
}

// Using EPPlus from nuget.
// Export grid method can be reused for all grids.
private FileContentResult Export(IGrid grid, String fileName)
{
    Int32 col = 1;
    using ExcelPackage package = new ExcelPackage();
    ExcelWorksheet sheet = package.Workbook.Worksheets.Add("Data");

    foreach (IGridColumn column in grid.Columns)
    {
        sheet.Cells[1, col].Value = column.Title;
        sheet.Column(col++).Width = 18;

        column.IsEncoded = false;
    }

    foreach (IGridRow<Object> row in grid.Rows)
    {
        col = 1;

        foreach (IGridColumn column in grid.Columns)
            sheet.Cells[row.Index + 2, col++].Value = column.ValueFor(row);
    }

    return File(package.GetAsByteArray(), "application/unknown", $"{fileName}.xlsx");
}
private IGrid<Person> CreateExportableGrid()
{
    IGrid<Person> grid = new Grid<Person>(repository.GetPeople());
    grid.ViewContext = new ViewContext { HttpContext = HttpContext };
    grid.Query = Request.Query;

    grid.Columns.Add(model => model.Name).Titled("Name");
    grid.Columns.Add(model => model.Surname).Titled("Surname");

    grid.Columns.Add(model => model.Age).Titled("Age");
    grid.Columns.Add(model => model.Birthday).Titled("Birthday").Formatted("{0:d}");
    grid.Columns.Add(model => model.IsWorking).Titled("Employed");

    // Pager should be excluded on export if all data is needed.
    grid.Pager = new GridPager<Person>(grid);
    grid.Processors.Add(grid.Pager);
    grid.Processors.Add(grid.Sort);
    grid.Pager.RowsPerPage = 6;

    foreach (IGridColumn column in grid.Columns)
    {
        column.Filter.IsEnabled = true;
        column.Sort.IsEnabled = true;
    }

    return grid;
}

@model IGrid<Person>

<a href="@(Url.Action("ExportIndex") + ViewContext.HttpContext.Request.QueryString)">Export</a>

@(new HtmlGrid<Person>(Html, Model))