Enable Python Toolbox parameters

[Manu]

I cannot enable parameters in a Python toolbox if they are conditionally disabled. My Toolbox code is as follows:

import os, shutil
import arcpy as ap
import arcgis
from arcgis.gis import GIS

global AGOL_TYPES
AGOL_TYPES = ["Feature Collection",
    "Feature Service",
    "KML",
    "KML Collection",
    "CSV"
    ]
class Toolbox(object):
    def __init__(self):
        self.label = "AGOL Backup"
        self.alias = "Backup"
        self.tools = [BackupLocal]

class BackupLocal(object):
    def __init__(self):
        self.label = "Backup"
        self.description = "Create local backup of ArcGis Online items."
        self.canTunInBackground = False
    
    def getParameterInfo(self):
        global AGOL_TYPES
        USR = ap.Parameter(
            displayName = "AGOL username",
            name = "usr",
            datatype = "GPString",
            parameterType = "Required",
            direction = "Input")
        PW = ap.Parameter(
            displayName = "Password",
            name = "psswrd",
            datatype = "GPEncryptedString",
            parameterType = "Optional",
            direction = "Input")
        COMPLETE = ap.Parameter(
            displayName = "Complete backup",
            name = "complete",
            datatype = "GPBoolean",
            parameterType = "Required",
            direction = "Input")
        COMPLETE.value = False
        OWNER = ap.Parameter(
            displayName = "Owner (if different from user)",
            name = "owner",
            datatype = "GPString",
            parameterType = "Optional",
            direction = "Input")
        OWNER.value = None
        DTYPES = ap.Parameter(
            displayName = "Data types",
            name = "dtypes",
            datatype = "GPString",
            parameterType = "Optional",
            direction = "Input",
            multiValue = True)
        DTYPES.filter.list = AGOL_TYPES
        TAGS = ap.Parameter(
            displayName = "Tags",
            name = "tags",
            datatype = "GPString",
            parameterType = "Optional",
            direction = "Input",
            multiValue = True)
        OVERWRITE = ap.Parameter(
            displayName = "Overwrite",
            name = "overwrite",
            datatype = "GPBoolean",
            parameterType = "Required",
            direction = "Input")
        OVERWRITE.value = False
        OUT_DIR = ap.Parameter(
            displayName = "Backup directory",
            name = "out_dir",
            datatype = "DEFolder",
            parameterType = "Required",
            direction = "Output")
        OUT_DIR.value = "F:/AGOL_backup"
        parameters = [USR, PW, COMPLETE, OWNER, DTYPES, TAGS, OVERWRITE, \
                      OUT_DIR]
        return parameters

    def isLicensed(self):
        return True

    def updateParameters(self, parameters):
        [USR, PW, COMPLETE, OWNER, DTYPES, TAGS, OVERWRITE, OUT_DIR] = \
            parameters
        if COMPLETE and COMPLETE.altered:
            OWNER.enabled = False
            DTYPES.enabled = False
            TAGS.enabled = False
        else:
            parameters[3].enabled = True
            OWNER.enabled = True
            DTYPES.enabled = True
            TAGS.enabled = True
        return

    def updateMessages(self, parameters):
        return

    def execute(self, parameters, messages):
        return

I want to show the OWNER, DTYPE and TAG parameters only if COMPLETE is set to False. However, even if the COMPLETE parameter is set to False, these parameters do not show up in the Toolbox interface. Why is that?

As you can see, this happens regardless of whether I call the parameters after assigning them to variables, or directly in the parameter list. Moreover, they do not show up despite the default value for COMPLETE being False, i.e., these parameters are hidden whenever there is just the possibility of their .enabled attribute being set to False.

[JohannesLindner · Accepted solution]

if COMPLETE and COMPLETE.altered:

You're not checking the value of the parameter, you're checking if a non-empty value is assigned to the variable COMPLETE.

Take a look at this code and its output:

test_values = [False, 0, None, "", [], ()]
for value in test_values:
    msg = str(value) + ": "
    if value:
        msg += "TRUE"
    else:
        msg += "FALSE"
    print(msg)

False: FALSE
0: FALSE
None: FALSE
: FALSE
[]: FALSE
(): FALSE

So, your if COMPLETE: could also be written as

if COMPLETE not in [False, 0, None, "", [], ()]:  # and maybe some other values, too

and that will always return False, because COMPLETE has a value (it is an arcpy.Parameter).

Instead, you have to check the value of that arcpy.Parameter:

if COMPLETE.value:

[Manu]

Oh, thanks. Today is not my day, it seems. I should have known that I need to access the value and not the parameter 😬