I'm wondering if using {} instead of [] for the list is an issue or whether in the end the set is being converted to a list by arcpy so it's no issue. ({} delineates a set [] delineates a list.)
As for Dan's comment about the local path. There are two options: os.path.dirname(sys.argv[0]) or os.path.dirname(__file__). Which is best depends on what you need -- usually __file__.
See: Difference between __file__ and sys.argv[0] (StackOverflow)
(In .tbx script tool validation code __file__ will be the path to the function - packed in the tbx file using a relative link syntax: u'C:\\test\\Toolbox.tbx#Script_z.InitializeParameters.py', sys.argv[0] will just give you an empty string as I would guess the validation code is being run with execfile().)
One more thing about path - maybe you instead want the path to the mxd? (Don't forget to import os at the top of your validatino code.)
here = os.path.dirname(arcpy.mapping.MapDocument("CURRENT").filePath)
Back to your original question: I would remove the if statement in the initialize code to make sure it always at least attempts to run.
def initializeParameters(self):
"""Refine the properties of a tool's parameters. This method is
called when the tool is opened."""
try:
self.params[1].filter.list = sorted(
[row[0] for row in arcpy.da.SearchCursor(
self.params[0].value, "ADMINAREANAME") if row[0]])
except:
pass
Gino's attached .py snippet is pretty short so I am including it here:
import arcpy
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."""
if self.params[0].value:
self.params[1].filter.list = sorted(
{row[0] for row in arcpy.da.SearchCursor(
self.params[0].value, "ADMINAREANAME") if row[0]})
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."""
if self.params[0].altered:
if self.params[0].value:
self.params[1].filter.list = sorted(
{row[0] for row in arcpy.da.SearchCursor(
self.params[0].value, "ADMINAREANAME") if row[0]})
return
def updateMessages(self):
"""Modify the messages created by internal validation for each tool
parameter. This method is called after internal validation."""
return
