This routine has been deprecated. Use the various ENVI parameter classes instead.

Each ENVITask has a set of required parameters (also called properties), each of which has constraints on data type, values, etc. The ENVITaskParameter function returns a reference to an object that lists the requirements for a given property of an ENVITask, along with its current settings.

Example

See the code example for ENVITask::Parameter.

Methods

QueryProperty

Validate

Properties

CHOICE_LIST (Get)

A string array that lists the possible values for the task property. If the property does not have a choice list, it returns a value of !NULL. The values of this property must adhere to, or be castable to, the TYPE property; otherwise it will not be set and an error will be issued. This property is not present for all values of TYPE. Use QueryProperty to learn if it is available.

DEFAULT (Get)

The default value of the task property. If the property does not have a default value, it returns a value of !NULL. The values of this property must adhere to, or be castable to, the TYPE property; otherwise it will not be set and an error will be issued.

DESCRIPTION (Get)

Text describing the purpose of the task property with respect to its parent task. It can also provide details of the values in CHOICE_LIST.

DIMENSIONS (Get)

If the task property requires more than one scalar, the string contains the array dimensions. This property is not present on a scalar parameter. Use QueryProperty to learn if it is available.

  • Example of a three-element array declaration: [3]
  • Example of a 1D array with any number of elements: [*]
  • Example of a 2D array with any number of columns or rows: [*, *]
  • Example of a 2D array with a specific number of elements: [3, 256]
  • Example of a 2D array with any number of columns and 3 rows: [*, 3]

DIRECTION (Get)

Whether the task property acts as INPUT or OUTPUT.

DISPLAY_NAME (Get)

The name of the task property as it appears in the user interface.

IS_DIRECTORY (Get)

Whether the task property is a directory URI or not. This property is present only when TYPE is ENVIURI.

MAX (Get)

The maximum value of the task property. This property is not present for all values of TYPE. Use QueryProperty to learn if it is available.

MIN (Get)

The minimum value of the task property. This property is not present for all values of TYPE. Use QueryProperty to learn if it is available.

NAME (Get)

The name of the task property.

REQUIRED (Get)

Whether or not the task property is optional (0) or required (1).

TYPE (Get)

A scalar string with one of the following:

  • IDL data type: Byte, Int, Long, Float, Double, Complex, String, DComplex, UInt, ULong, Long64, or ULong64
  • The required class for the parameter (for example, ENVIRaster). Scalars of IDL Lists, Hashes, Ordered Hashes, and Dictionaries are supported; arrays are not. To specify arrays, declare TYPE as a List and convert the array of IDL containers to a List.
  • Boolean type (Bool)
  • ENVIURI: Indicates that a uniform resource indicator (URI) is required. For a local file, specify a scalar string that is a fully qualified file path. For a remote file, specify a string with the direct URL of the dataset.

If the task property requires more than one scalar, the string will end with the Array suffix, and the DIMENSIONS property will be present.

VALUE (Get, Set)

The current value of the task property. If TYPE is Boolean, VALUE can be an integer (0 or 1) or a string (true or false). When this property is set, the input value will be validated, throwing an exception on failure. A CATCH block is needed to avoid program termination, or you can call the Validate method first to verify the input value is allowed for this property.

 

Note: To learn about other properties listed in the return value of QueryProperty, see the descriptions under the IDLParameterType class, where Type is the TYPE property value.

Version History

ENVI 5.1

Introduced

ENVI 5.2

Changed DIRECTION property values to INPUT and OUTPUT only.

Added DISPLAY_NAME, MAX, and MIN properties.
ENVI 5.4

Added DIMENSIONS and IS_DIRECTORY properties.

Changed CHOICE_LIST, MAX, MIN, VALUE properties. Added QueryProperty method.

ENVI 5.4.1

 Deprecated

API Version

4.2

See Also

ENVITask, ENVITaskParameter::QueryProperty, ENVITaskParameter::Validate