Property :: readOnly - Is property read only

The read-only state is an instance or value state (but not a collection state). There are several reasons for instances and values for getting the read-only state.

An attribute is read-only when the instance it belongs to has been set to read-only for some reason (used by another user, cannot be updated by current user or others).

Instances in a collection are usually set to read-only when the instance selected has been set to read only (context action), but it might also be temporary or persistent write protected (e.g. when being locked in workspaces).

Since MEMO properties are stored as separate instances, a MEMO property can be read-only, even though the parent instance can be updated (e.g. when being locked in a transaction). Moreover, any property can be set to read-only by setting the context property PropertyContext::readOnly().

Attributes and MEMO fields with read-only state cannot be updated.

The property returns, whether the value/instance selected in the property is read-only (true) or not (false). The property throws an exception, when the property handle is not valid or no instance could be selected.