<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def OnItemSelected(self, event):
 """Item selection event handler"""


        value = event.m_itemIndex
        self.startIndex = value

        self.switching = True
        post_command_event(self, self.GridActionTableSwitchMsg, newtable=value)
        self.switching = False

        event.Skip()