Disable PYT toolbox parameter

[CarlBeyerhelm]

I’m tasked with modifying an existing PYT toolbox…a format I’m not familiar with.

I do have pretty good experience with non-PYT tools, and with configuring their ToolValidator code.

What I’d like to do is modify the PYT so that it will open with one of the parameters in a disabled state, but I’m not sure if the code format is the same as in a ToolValidator class…like params[5].enabled = False…and I’m not sure where in the PYT to place that code.

Can anyone offer advice, please?  Thank you!

[JohannesLindner · Accepted solution]

You can change the parameter states and values in getParameterInfo() and updateParameters(). You can change parameter warnings and errors in updateMessages().

In your case, you would do something like this:

class SomeTool:
    label = "SomeTool"

    def getParameterInfo(self):
        # define the parameters
        parameters = [
            arcpy.Parameter(...),
            arcpy.Parameter(...),
            arcpy.Parameter(...),
            ]
        # change default values, filters, and visibility
        parameters[0].filter.list = [1, 2, 3]
        parameters[1].enabled = False
        parameters[2].value = "default"
        return parameters

    def updateParameters(self, parameters):
        if parameters[0].value == 1:
            parameters[1].enabled = True
        else:
            parameters[1].enabled = False

    def updateMessages(self, parameters):
        parameters[0].setWarningMessage("You have been warned")

For more, here'S the official doc: https://pro.arcgis.com/en/pro-app/latest/arcpy/classes/parameter.htm 

[CarlBeyerhelm]

Perfect!  Thank you.

I'd been trying to use the params[5].enabled = False format from ToolValidator instead of parameters[5].enabled = False.