wxPython/samples/wxPIA_book/Chapter-13/list_report_virtual.py

   1 import wx
   2 import sys, glob, random
   3 import data
   4
   5 class DataSource:
   6     """
   7     A simple data source class that just uses our sample data items.
   8     A real data source class would manage fetching items from a
   9     database or similar.
  10     """
  11     def GetColumnHeaders(self):
  12         return data.columns
  13
  14     def GetCount(self):
  15         return len(data.rows)
  16
  17     def GetItem(self, index):
  18         return data.rows[index]
  19
  20     def UpdateCache(self, start, end):
  21         pass
  22
  23
  24 class VirtualListCtrl(wx.ListCtrl):
  25     """
  26     A generic virtual listctrl that fetches data from a DataSource.
  27     """
  28     def __init__(self, parent, dataSource):
  29         wx.ListCtrl.__init__(self, parent,
  30             style=wx.LC_REPORT|wx.LC_SINGLE_SEL|wx.LC_VIRTUAL)
  31         self.dataSource = dataSource
  32         self.Bind(wx.EVT_LIST_CACHE_HINT, self.DoCacheItems)
  33         self.SetItemCount(dataSource.GetCount())
  34
  35         columns = dataSource.GetColumnHeaders()
  36         for col, text in enumerate(columns):
  37             self.InsertColumn(col, text)
  38
  39
  40     def DoCacheItems(self, evt):
  41         self.dataSource.UpdateCache(
  42             evt.GetCacheFrom(), evt.GetCacheTo())
  43
  44     def OnGetItemText(self, item, col):
  45         data = self.dataSource.GetItem(item)
  46         return data[col]
  47
  48     def OnGetItemAttr(self, item):  return None
  49     def OnGetItemImage(self, item): return -1
  50
  51
  52
  53 class DemoFrame(wx.Frame):
  54     def __init__(self):
  55         wx.Frame.__init__(self, None, -1,
  56                           "Virtual wx.ListCtrl",
  57                           size=(600,400))
  58
  59         self.list = VirtualListCtrl(self, DataSource())
  60
  61
  62
  63 app = wx.PySimpleApp()
  64 frame = DemoFrame()
  65 frame.Show()
  66 app.MainLoop()