ToolValidator class

Discussion created by rangermry on Oct 4, 2013
I am writing a tool to generate a MXD and some metadata.  It works but I am wondering if there is a better way than I am using to write the Tool Validator class than I am?  Wondering how I would add another value list (not derived)?  My value list now is to pick a mxd from a list of mxds in a template folder.  I would like to add a value list to make a liks of layer files to add from a folder of template layer files.   I would not mind changing below code so getting the list of mxds from a folder is a seperate function, but when I do that I get errors.
import arcpy
import os
class ToolValidator(object):
  """Class for validating a tool's parameter values and controlling
  the behavior of the tool's dialog."""

  def __init__(self):
    """Setup arcpy and the list of tool parameters."""
    self.params = arcpy.GetParameterInfo()

  def initializeParameters(self):
    """Refine the properties of a tool's parameters.  This method is
    called when the tool is opened."""

  def updateParameters(self):
    """Modify the values and properties of parameters before internal
    validation is performed.  This method is called whenever a parameter
    has been changed."""
    folderPath=r"folderPathHere"#Folder of Map Templates
    mapTemplates = []
    for filename in os.listdir(folderPath):
        fullpath = os.path.join(folderPath, filename)
        if os.path.isfile(fullpath):
            basename, extension = os.path.splitext(fullpath)
            if extension.lower() == ".mxd":
    self.params[0].filter.list = mapTemplates

  def updateMessages(self):
    """Modify the messages created by internal validation for each tool
    parameter.  This method is called after internal validation."""