Easy question on Parameters

JoshV

Hello All-

I have a python script that I have imported into my toolbox.  I need three Parameters for this script and I found it easiest to use ArcToolbox.  by right clicking the script, I go to properties and then to Parameters.  I added a Parameter called Input_Data of Type "Feature Layer".  I added a second Parameter of Type "Field" and set it to be Obtained from Input_Data so that it will show all the Attributes of that Layer.  My third Parameter is the question I have.. I want it to show all the Values of whichever Attribute is Selected but when I add the Parameter of Type "Field" and select Obtained from, it only shows Input_Data as an option and not the second Parameter.  How can I do this?  I created a picture but unfortunately the ESRI site isn't allowing any attachments at the moment.

MaryM

I wanted to do this same thing for having a list of MXDs show in a drop down list on a tool.  I understand the easy way to add a List of Values manually.  However, I want one to be auto-generated in case an MXD is added in a certain folder.  I tried copying this a bit but I do not understand it so much.  Do you need to add anything in the main code of the tool to signify this information in the Validation code?  Where is it that it assigns the list generated to the filter list?

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()
    self.mapTemplateParam = self.params[0]
    self.type1Param = self.params[1]
    return

  def initializeParameters(self):
    """Refine the properties of a tool's parameters.  This method is
    called when the tool is opened."""
    self.mapTemplateParam.Value = self.mapTemplateParam.filter.list[0]
    self.getMapTemlateList();
    return

  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."""
    self.getMapTemplateList()
    return

  def getMapTemplateList(self):
    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":
                mapTemplates.append(fullpath)
    self.mapTemplateParam.filter.list = mapTemplates
    return

I get error line 4, line 18 and a IndexError: list index out of range?