Résumé
Every tool parameter has an associated Parameter object with properties and methods that are useful in tool validation.
Discussion
Although many Parameter object properties are read/write, most of these properties can only be set or modified when you initially create or modify the object. Several properties, including name, displayName, datatype, direction, and parameterType, establish the characteristics of a tool and cannot be modified during validation methods (such as updateMessages and updateParameters).
Syntaxe
Parameter ({name}, {displayName}, {direction}, {datatype}, {parameterType}, {enabled}, {category}, {symbology}, {multiValue})
Paramètre | Explication | Type de données |
name | The parameter name. (La valeur par défaut est None) | String |
displayName | The parameter label as shown on the tool's dialog box. (La valeur par défaut est None) | String |
direction | The Input/Output direction of the parameter. (La valeur par défaut est None) | String |
datatype | The data type of the parameter. For a list of parameter data types, see Geoprocessing data types. (La valeur par défaut est None) | String |
parameterType | parameterType can be Required, Optional, or Derived. Derived means that the user of your tool does not enter a value for the parameter. Derived types are always output parameters. (La valeur par défaut est None) | String |
enabled | False if the parameter is unavailable. (La valeur par défaut est None) | Boolean |
category | The category of the parameter. (La valeur par défaut est None) | String |
symbology | The path to a layer file (.lyr or .lyrx) used for drawing the output. (La valeur par défaut est None) | String |
multiValue | True if the parameter is a multivalue parameter. (La valeur par défaut est None) | Boolean |
Propriétés
Propriété | Explication | Type de données |
altered (Lecture seule) | True if the user has modified the value. | Boolean |
category (Lecture et écriture) | The category of the parameter. | String |
columns (Lecture et écriture) | The column data types and names of a value table parameter are set using a list of lists.
| String |
datatype (Lecture et écriture) | The data type of the parameter. For a list of parameter data types, see Geoprocessing data types. | String |
defaultEnvironmentName (Lecture et écriture) | The geoprocessing environment setting used to set the parameter's default value. | String |
direction (Lecture et écriture) | The Input/Output direction of the parameter. | String |
displayName (Lecture et écriture) | The parameter label as shown on the tool's dialog box. | String |
displayOrder (Lecture et écriture) | The order in which a parameter is displayed on the tool's dialog box. This may be different from the order the parameters are accessed from Python. | Integer |
enabled (Lecture et écriture) | False if the parameter is unavailable. | Boolean |
filter (Lecture seule) | The filter to apply to values in the parameter. | Filter |
filters (Lecture et écriture) | Similar to filter but used to support value table parameters.
| Filter |
hasBeenValidated (Lecture seule) | True if the internal validation routine has checked the parameter. | Boolean |
message (Lecture seule) | The message to be displayed to the user. | String |
multiValue (Lecture et écriture) | True if the parameter is a multivalue parameter. | Boolean |
name (Lecture et écriture) | The parameter name. | String |
parameterDependencies (Lecture et écriture) | A list of indexes of each dependent parameter. In a script tool, parameterDependencies is set with a list of parameter indexes; in a Python toolbox tool, parameterDependencies is set with a list of parameter names. | Integer |
parameterType (Lecture et écriture) | parameterType can be Required, Optional, or Derived. Derived means that the user of your tool does not enter a value for the parameter. Derived types are always output parameters.
| String |
schema (Lecture seule) | The schema of the output dataset. | Schema |
symbology (Lecture et écriture) | The path to a layer file (.lyr or .lyrx) used for drawing the output. | String |
value (Lecture et écriture) | The value of the parameter. | Object |
valueAsText (Lecture seule) | The value of the parameter as a string. Remarque :For Python toolboxes only. | String |
values (Lecture et écriture) | The values of the Value Table parameter, which is set using a list of lists. | Variant |
Vue d’ensemble des méthodes
Méthode | Explication |
clearMessage () | Clears out any message text and sets the status to informative (no error or warning). |
hasError () | Returns True if the parameter contains an error. To evaluate whether a parameter has an error, hasError should be called within the tool validation's updateMessages method. |
hasWarning () | Returns True if the parameter contains a warning. |
isInputValueDerived () | Returns True if the tool is being validated inside a Model and the input value is the output of another tool in the model. |
setErrorMessage (message) | Sets a parameter as having an error with the supplied message. Tools do not execute if any of the parameters have an error. |
setIDMessage (message_type, message_ID, {add_argument1}, {add_argument2}) | Sets a parameter as having a system message. |
setWarningMessage (message) | Sets a parameter as having an error with the supplied message. Unlike errors, tools will execute with warning messages. |
Méthodes
clearMessage ()
hasError ()
Type de données | Explication |
Boolean | True if the parameter contains an error. |
hasWarning ()
Type de données | Explication |
Boolean | True if the parameter contains a warning. |
isInputValueDerived ()
Type de données | Explication |
Boolean | True if the tool is being validated inside a Model and the input value is the output of another tool in the model. |
setErrorMessage (message)
Paramètre | Explication | Type de données |
message | The string to be added as an error message to the geoprocessing tool messages. | String |
setIDMessage (message_type, message_ID, {add_argument1}, {add_argument2})
Paramètre | Explication | Type de données |
message_type | Defines whether the message will be an error or a warning.
| String |
message_ID | The message ID allows you to reference existing system messages. | 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. The data type is variable depending on the message. | 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. The data type is variable depending on the message. | Object |
setWarningMessage (message)
Paramètre | Explication | Type de données |
message | The string to be added as a warning message to the geoprocessing tool messages. | String |
Exemple de code
Enabling or disabling a parameter in a ToolValidator class.
def updateParameters(self):
# If the option to use a weights file ("Get Spatial Weights From File")
# is selected, enable the parameter for specifying the file;
# otherwise, disable it
if self.params[3].value == "Get Spatial Weights From File":
self.params[8].enabled = True
else:
self.params[8].enabled = False
return
Setting a default value for a parameter in a ToolValidator class.
def updateParameters(self):
# Set the default distance threshold to 1/100 of the larger of
# the width or height of the extent of the input features. Do
# not set if there is no input dataset yet, or the user has set
# a specific distance (Altered is true).
if self.params[0].value:
if not self.params[6].altered:
extent = arcpy.Describe(self.params[0].value)
width = extent.XMax - extent.XMin
height = extent.YMax - extent.YMin
if width < height:
self.params[6].value = width / 100
else:
self.params[6].value = height / 100
return
Setting a custom error message for a parameter in a ToolValidator class.
def updateMessages(self):
self.params[6].clearMessage()
# Check to see if the threshold distance contains a value of
# zero and the user has specified a fixed distance band.
if self.params[6].value <= 0:
if self.params[3].value == "Fixed Distance Band":
self.params[6].setErrorMessage(
"Zero or a negative distance is invalid when "
"using a fixed distance band. Please use a "
"positive value greater than zero.")
elif self.params[6].value < 0:
self.params[6].setErrorMessage(
"A positive distance value is required when "
"using a fixed distance band. Please specify "
"a distance.")
return
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