AddIDMessage (arcpy)

Summary

Allows you to use system messages with a script tool. A list of messages and IDs that can be used are provided under Understanding geoprocessing tool errors and warnings.

Discussion

Geoprocessing errors and warnings are returned from geoprocessing tools with a six-digit code and a text message. Every error and warning has a corresponding description page in the desktop help system. This page contains both a detailed description of the error and possible solutions for the error. In tool dialog boxes, the Python window, and the Results window, the ID code is a link that, when clicked, takes you to a description page.

Syntax

AddIDMessage (message_type, message_ID, {add_argument1}, {add_argument2})

Parameter	Explanation	Data Type
message_type	The message type defines whether the message will be an error, warning, or informative. Valid message types are: ERROR —Adds an error message to the tool messages. INFORMATIVE —Adds an informative message to the tool messages. WARNING —Adds a warning message to the tool messages.	String
message_ID	The message ID allows you to reference existing messages for your scripting errors and warnings.	Integer
add_argument1	Depending on which message ID is used, an argument may be necessary to complete the message. Common examples include dataset or field names. Datatype can be string, integer, or double.	Object
add_argument2	Depending on which message ID is used, an argument may be necessary to complete the message. Common examples include dataset or field names. Datatype can be string, integer, or double.	Object

Code Sample

AddIDMessage example

Add a message to a Python script tool.

class overwriteError(Exception):
    pass

import arcpy

in_feature_class = arcpy.GetParameterAsText(0)
out_feature_class = arcpy.GetParameterAsText(1)

try:
    # If the output feature class already exists, raise an error
    if arcpy.Exists(in_feature_class):
        # Raise a custom exception
        raise overwriteError(out_feature_class)
    else:
        arcpy.CopyFeatures_management(in_feature_class, out_feature_class)

except overwriteError as err:
    # Use message ID 12, and provide the output feature class
    #    to complete the message.
    arcpy.AddIDMessage("Error", 12, str(err))