Appendix A: Controlling iTools from the IDL Command Line 389
iTool Developer’s Guide Changing Property Values
Changing Property Values
Given the object identifier for a property, there are two ways to change the property
value: using the DoSetProperty method of the IDLitTool class, and using the
SetProperty method of the IDLitComponent class. When changing the value of a
registered property, in most cases, it is better to use the DoSetProperty method.
Using the DoSetProperty Method
Use the DoSetProperty method of the IDLitTool class to change the value of a
property associated with an item in the iTool hierarchy. Using the DoSetProperty
method has two advantages over using the SetProperty method:
1. DoSetProperty takes an object identifier as its argument; there is no need to
retrieve the object reference to the property you wish to change.
2. The DoSetProperty method takes care of adding the property change to the
iTool’s undo-redo buffer.
Warning
To use the DoSetProperty method, the property whose value is being changed must
be a registered property of the selected iTool component object. If the property is
not registered, use the SetProperty method instead.
For example, suppose you have created an iPlot tool with the following command:
IPLOT, RANDOMU(seed, 15)
To change the color of the plot line, you could use the following statements:
idTool = ITGETCURRENT(TOOL=oTool)
idPlot = oTool->FindIdentifiers('*plot', /VISUALIZATIONS)
success = oTool->DoSetProperty(idPlot, 'COLOR', [40,120,200])
oTool->CommitActions
Warning
Make sure you understand what the FindIdentifiers method will return for a given
search string and keyword; care is necessary to ensure that you retrieve the
identifier for the correct item. See “Retrieving Component Identifiers” on page 382
for details.
Note that the property identifier used as the second argument to the DoSetProperty
method is often, but not always, the same as the property name that is displayed in the
