Making Parameter List Update/Refresh in Python Toolbox?

Question

I am using a python toolbox in ArcGIS 10.2.2 and want a drop down list of all the versions for the person reconciling to choose from. (And I do not want to include dbo.DEFAULT and DS.Draft). But this list is populated right after a script is run to create the editor's version and if the Python Toolbox isn't refreshed manually in ArcMap, then this newest version doesn't show up in the list.

I looked at updateParameters, but either I was writing it incorrectly or it doesn't work because the user isn't actually changing a parameter that triggers it.

Regardless, I want to refresh the list at the time the script is run.

Can I use updateParameters or do a reload or something else snazzy that will make the list repopulate?

The other thing is I could switch the order of the parameters and having the user type their initials first which would then be a user action that could trigger the updateParmaters, but not sure this is the issue and seems convoluted.

import sys, arcpy, os

class Toolbox(object):
    def __init__(self):
        """Define the toolbox (the name of the toolbox is the name of the
        .pyt file)."""
        self.label = "EGDB Data Steward Version"
        self.alias = ""

        # List of tool classes associated with this toolbox
        self.tools = [Prep]

class Prep(object):
    def __init__(self):
        """Define the tool (tool name is the name of the class)."""
        self.label = "Prepare for Reconcile and Post"
        self.description = "Create grandfather version of editor for DS"
        self.canRunInBackground = False

    def getParameterInfo(self):
    #Define parameter definitions
        params = []  

    # First parameter
        param0 = arcpy.Parameter(
            displayName="Editor's Version Name",
            name="editor_full_versionname",
            datatype="GPString",
            parameterType="Required",
            direction="Input")

        param0.filter.type = "ValueList"
        param0.filter.list = [v.name for v in arcpy.da.ListVersions(r"\\inpyosegis05\DatabaseConnectionFiles\DataStewardsOnly\YOSEGIS_VectorYOSE_DS.sde")
                              if v.name not in ["dbo.DEFAULT", "DS.Draft"]]  #Take DEFAULT and Draft off the drop-down list as choices.

    # Second parameter
        param1 = arcpy.Parameter(
            displayName="Data Steward's Initials",
            name="DS_initials",
            datatype="GPString",
            parameterType="Required",
            direction="Input")

        params = [param0, param1]
        return params

def isLicensed(self):
    """Set whether tool is licensed to execute."""
    return True

def updateParameters(self, parameters):
    """Modify the values and properties of parameters before internal
    validation is performed.  This method is called whenever a parameter
    has been changed."""
    param0 = arcpy.Parameter(
        displayName="Editor's Version Name",
        name="editor_full_versionname",
        datatype="GPString",
        parameterType="Required",
        direction="Input")

    param0.filter.type = "ValueList"
    param0.filter.list = [v.name for v in arcpy.da.ListVersions(r"\\inpyosegis05\DatabaseConnectionFiles\DataStewardsOnly\YOSEGIS_VectorYOSE_DS.sde")
                          if v.name not in ["dbo.DEFAULT", "DS.Draft"]]  #Take DEFAULT and Draft off the drop-down list as choices.
    return 

Answer 1

Try the following:

def updateParameters(self, parameters):
    if parameters[0].value:
        parmeters[0].filter.list = [v.name for v in arcpy.da.ListVersions(r"\\inpyosegis05\DatabaseConnectionFiles\DataStewardsOnly\YOSEGIS_VectorYOSE_DS.sde") 
                                    if v.name not in ["dbo.DEFAULT", "DS.Draft"]]
    return