class MyModelAdmin(admin.ModelAdmin):   

    def changelist_view(self, request, extra_context=None):

        if not request.GET.has_key('decommissioned__exact'):

            q = request.GET.copy()
            q['decommissioned__exact'] = 'N'
            request.GET = q
            request.META['QUERY_STRING'] = request.GET.urlencode()
        return super(MyModelAdmin,self).changelist_view(request, extra_context=extra_context)

为了实现这一点，并在侧边栏中有一个可用的“全部”链接（即显示全部而不显示未决的链接），你需要创建一个自定义列表过滤器，django.contrib.admin.filters.SimpleListFilter默认情况下继承并过滤“待处理”。遵循这些原则的方法应该起作用：

from datetime import date

from django.utils.translation import ugettext_lazy as _
from django.contrib.admin import SimpleListFilter

class StatusFilter(SimpleListFilter):
    title = _('Status')

    parameter_name = 'status'

    def lookups(self, request, model_admin):
        return (
            (None, _('Pending')),
            ('activate', _('Activate')),
            ('rejected', _('Rejected')),
            ('all', _('All')),
        )

    def choices(self, cl):
        for lookup, title in self.lookup_choices:
            yield {
                'selected': self.value() == lookup,
                'query_string': cl.get_query_string({
                    self.parameter_name: lookup,
                }, []),
                'display': title,
            }

    def queryset(self, request, queryset):
        if self.value() in ('activate', 'rejected'):
            return queryset.filter(status=self.value())    
        elif self.value() == None:
            return queryset.filter(status='pending')


class Admin(admin.ModelAdmin): 
    list_filter = [StatusFilter]