AddIDMessage

Summary

Use system ID messages with a script tool.

Discussion

For script tools, you can create your own errors and warnings using the AddWarning and AddError functions. Alternatively, you can also use any of the standard error or warning messages using the AddIDMessage function.

However, to reuse a standard error or warning, you must first know the six-digit code. This will require some research on your part; you will have to search the descriptions found in the help to find the right six-digit code. Once you've identified an appropriate ID, make note of any additional information that needs to be included in the message, usually denoted as <value>.

Syntax

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

Parameter	Explanation	Data Type
message_type	Specifies the message severity. 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. Data type 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. Data type can be string, integer, or double.	Object

Code sample

AddIDMessage example

Add a message to a Python script tool. The Python sample below checks to see whether a feature class has been provided as input and, if not, uses the AddIDMessage function to return ID code 12 (000012: <value> already exists). The optional argument is used to substitute the feature class name into the message.

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))