Defining parameters for Python Toolbox tool in ArcGIS Pro

Question

I have been posting similar questions recently, but I found a template code for a Python toolbox and I would like more help.

I am trying to create a tool in ArcGIS Pro that takes parameters from users (initially, the geodatabase filename) and shows the report on the screen.

I added to the template the function "getParameter." I thought this function will open up a dialog box for a user to choose a parameter, but it does not for some reason.

The following code has no syntax error. When I add a new Python toolbox and ran this code, it does run, but it says "no parameters," as the screenshot says. What change do I need to make?

import arcpy
import os


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

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


class Report(object):
    def __init__(self):
        """Define the tool (tool name is the name of the class)."""
        self.label = "Tool"
        self.description = ""
        self.canRunInBackground = False


    def getParameter(self):  
        arcpy.env.workspace = arcpy.GetParameterAsText(0)

        featureclasses = arcpy.ListFeatureClasses()
        for fc = in featureclasses:
            print (fc)

    def getParameterInfo(self):
        """Define parameter definitions"""
        params = None
        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."""
        return

    def updateMessages(self, parameters):
        """Modify the messages created by internal validation for each tool
        parameter.  This method is called after internal validation."""
        return

    def execute(self, parameters, messages):
        """The source code of the tool."""
        return

Answer 1

I suggest you look at the Python Toolbox documentation, particularly:

• Defining parameters in a Python toolbox
• Defining parameter data types in a Python toolbox
• Accessing parameters within a Python toolbox

Your code was not working because:

• your getParameterInfo method was returning None instead of a list of Parameter definitions
• Your getParameter method will never get called as it's not part of the python toolbox API
• Your execute method did nothing.

Here's a working example

import arcpy

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

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


class Report(object):
    def __init__(self):
        """Define the tool (tool name is the name of the class)."""
        self.label = "Tool"
        self.description = ""
        self.canRunInBackground = True

    def getParameterInfo(self):
        # Define parameter definitions

        params = []

        # First parameter
        param0 = arcpy.Parameter(
            displayName="Input workspace",
            name="in_workspace",
            datatype="DEWorkspace",
            parameterType="Required",
            direction="Input")

        params.append(param0)
        return params


    def execute(self, parameters, messages):
        """The source code of the tool."""

        arcpy.env.workspace = parameters[0].valueAsText

        featureclasses = arcpy.ListFeatureClasses()
        for fc in featureclasses:
            messages.addMessage(fc)