Zusammenfassung
Every tool parameter has an associated Parameter object with properties and methods that are useful in tool validation.
Auswertung
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).
Syntax
Parameter ({name}, {displayName}, {direction}, {datatype}, {parameterType}, {enabled}, {category}, {symbology}, {multiValue})
Parameter | Erklärung | Datentyp |
name | The parameter name. (Der Standardwert ist None) | String |
displayName | The parameter label as shown on the tool's dialog box. (Der Standardwert ist None) | String |
direction | The Input/Output direction of the parameter. (Der Standardwert ist None) | String |
datatype | The data type of the parameter. For a list of parameter data types, see Geoprocessing data types. (Der Standardwert ist 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. (Der Standardwert ist None) | String |
enabled | False if the parameter is unavailable. (Der Standardwert ist None) | Boolean |
category | The category of the parameter. (Der Standardwert ist None) | String |
symbology | The path to a layer file (.lyr or .lyrx) used for drawing the output. (Der Standardwert ist None) | String |
multiValue | True if the parameter is a multivalue parameter. (Der Standardwert ist None) | Boolean |
Eigenschaften
Eigenschaft | Erklärung | Datentyp |
altered (Nur lesen) | True if the user has modified the value. | Boolean |
category (Lesen und schreiben) | The category of the parameter. | String |
columns (Lesen und schreiben) | The column data types and names of a value table parameter are set using a list of lists.
| String |
datatype (Lesen und schreiben) | The data type of the parameter. For a list of parameter data types, see Geoprocessing data types. | String |
defaultEnvironmentName (Lesen und schreiben) | The geoprocessing environment setting used to set the parameter's default value. | String |
direction (Lesen und schreiben) | The Input/Output direction of the parameter. | String |
displayName (Lesen und schreiben) | The parameter label as shown on the tool's dialog box. | String |
displayOrder (Lesen und schreiben) | 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 (Lesen und schreiben) | False if the parameter is unavailable. | Boolean |
filter (Nur lesen) | The filter to apply to values in the parameter. | Filter |
filters (Lesen und schreiben) | Similar to filter but used to support value table parameters.
| Filter |
hasBeenValidated (Nur lesen) | True if the internal validation routine has checked the parameter. | Boolean |
message (Nur lesen) | The message to be displayed to the user. | String |
multiValue (Lesen und schreiben) | True if the parameter is a multivalue parameter. | Boolean |
name (Lesen und schreiben) | The parameter name. | String |
parameterDependencies (Lesen und schreiben) | 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 (Lesen und schreiben) | 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 (Nur lesen) | The schema of the output dataset. | Schema |
symbology (Lesen und schreiben) | The path to a layer file (.lyr or .lyrx) used for drawing the output. | String |
value (Lesen und schreiben) | The value of the parameter. | Object |
valueAsText (Nur lesen) | The value of the parameter as a string. Hinweis:For Python toolboxes only. | String |
values (Lesen und schreiben) | The values of the Value Table parameter, which is set using a list of lists. | Variant |
Methodenübersicht
Methode | Erklärung |
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) | Marks the 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}) | Allows you to set a system message. |
setWarningMessage (message) | Marks the parameter as having a warning with the supplied message. Unlike errors, tools will execute with warning messages. |
Methoden
clearMessage ()
hasError ()
Datentyp | Erklärung |
Boolean | True if the parameter contains an error. |
hasWarning ()
Datentyp | Erklärung |
Boolean | True if the parameter contains a warning. |
isInputValueDerived ()
Datentyp | Erklärung |
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)
Parameter | Erklärung | Datentyp |
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})
Parameter | Erklärung | Datentyp |
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 datatype 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 datatype is variable depending on the message. | Object |
setWarningMessage (message)
Parameter | Erklärung | Datentyp |
message | The string to be added as a warning message to the geoprocessing tool messages. | String |
Codebeispiel
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