Admin actions are functions that take three arguments, as follows:

• The current ModelAdmin value
• The current HttpRequest value
• The QuerySet value containing the selected items

Perform the following steps to create a custom admin action to export a spreadsheet:

1. Create an export_xlsx() function in the admin.py file of the products app, as follows:

# products/admin.py
from copy import copy
from openpyxl import Workbook
from openpyxl.styles import Alignment, NamedStyle, builtins
from openpyxl.styles.numbers import FORMAT_NUMBER
from openpyxl.writer.excel import save_virtual_workbook

from django.http.response import HttpResponse
from django.utils.translation import ugettext_lazy as _
# ... other imports ...

def export_xlsx(modeladmin, request, queryset):
    wb = Workbook()
    ws = wb.active
    ws.title = "Products"

    number_alignment = Alignment(horizontal="right")
    wb.add_named_style(NamedStyle("Identifier",
                                  alignment=number_alignment,
                                  number_format=FORMAT_NUMBER))
    wb.add_named_style(NamedStyle("Normal Wrapped",
                                  alignment=Alignment(
                                      wrap_text=True)))

    number_headline_1 = copy(builtins.styles["Headline 1"])
    number_headline_1.name = "Number Headline 1"
    number_headline_1.alignment = number_alignment
    wb.add_named_style(number_headline_1)

    class Config():
        def __init__(self,
                     heading,
                     width=None,
                     heading_style="Headline 1",
                     style="Normal Wrapped"):
            self.heading = heading
            self.width = width
            self.heading_style = heading_style
            self.style = style

    column_config = {
        "A": Config("ID",
                    width=10,
                    heading_style="Number Headline 1",
                    style="Identifier"),
        "B": Config("Title", width=30),
        "C": Config("Description", width=60),
        "D": Config("Price ($)",
                    width=15,
                    heading_style="Number Headline 1", 
                    style="Currency"),
        "E": Config("Preview", width=100, style="Hyperlink"),
    }

    # Set up column widths, header values and styles
    for col, conf in column_config.items():
        ws.column_dimensions[col].width = conf.width

        column = ws[f"{col}1"]
        column.value = conf.heading
        column.style = conf.heading_style

    # Add products
    for obj in queryset.order_by("pk"):
        project_photos = obj.productphoto_set.all()[:1]
        url = ""
        if project_photos:
            url = project_photos[0].photo.url

        data = [obj.pk, obj.title, obj.description, obj.price, url]
        ws.append(data)

        row = ws.max_row
        for row_cells in ws.iter_cols(min_row=row, max_row=row):
            for cell in row_cells:
                cell.style = column_config[cell.column].style

    mimetype = "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet"
    charset = "utf-8"
    response = HttpResponse(
        content=save_virtual_workbook(wb),
        content_type=f"{mimetype}; charset={charset}",
        charset=charset)
    response["Content-Disposition"] = "attachment; filename=products.xlsx"
    return response


export_xlsx.short_description = _("Export XLSX")

2. Then, add the actions setting to ProductAdmin, as follows:

class ProductAdmin(admin.ModelAdmin): 
    # ... 
    actions = [export_xlsx]