Added admin change url chapter

docs/many_to_many.rst

@@ -25,4 +25,4 @@ You will see a column for children like this:
 
 .. image:: related_fk_display.png
 
-You can use the same method for M2M relations as well.
+You can use the same method for M2M relations as well. You should also read :doc:`object_url`.

docs/object_url.rst

@@ -1,2 +1,27 @@
 How to get Django admin urls for specific objects?
 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+
+You have a children column displatying the names of each heroes' children. You have been asked to link each children to the change page. You can do it like this.::
+
+    @admin.register(Hero)
+    class HeroAdmin(admin.ModelAdmin, ExportCsvMixin):
+        ...
+
+        def children_display(self, obj):
+            display_text = ", ".join([
+                "<a href={}>{}</a>".format(
+                        reverse('admin:{}_{}_change'.format(obj._meta.app_label, obj._meta.model_name),
+                        args=(child.pk,)),
+                    child.name)
+                 for child in obj.children.all()
+            ])
+            if display_text:
+                return mark_safe(display_text)
+            return "-"
+
+The :code:`reverse('admin:{}_{}_change'.format(obj._meta.app_label, obj._meta.model_name), args=(child.pk,))`, gives the change url for an object.
+
+The other options are
+
+* Delete: reverse('admin:{}_{}_delete'.format(obj._meta.app_label, obj._meta.model_name), args=(child.pk,))
+* History: reverse('admin:{}_{}_history'.format(obj._meta.app_label, obj._meta.model_name), args=(child.pk,))

heroes_and_monsters/entities/admin.py

@@ -7,7 +7,7 @@
 import sys
 from django.http import HttpResponse, HttpResponseRedirect
 from django.utils.safestring import mark_safe
-from django.urls import path
+from django.urls import path, reverse
 
 
 class IsVeryBenevolentFilter(admin.SimpleListFilter):
@@ -73,9 +73,16 @@ def headshot_image(self, obj):
 
     def children_display(self, obj):
         display_text = ", ".join([
-            child.name for child in obj.children.all()
+            "<a href={}>{}</a>".format(
+                reverse('admin:{}_{}_change'.format(obj._meta.app_label, obj._meta.model_name),
+                    args=(child.pk,)),
+                child.name)
+             for child in obj.children.all()
         ])
-        return display_text or "-"
+        if display_text:
+            return mark_safe(display_text)
+        return "-"
+
     children_display.short_description = "Children"
 
     # def get_readonly_fields(self, request, obj=None):