company logo

PropertyHandle :: Previous - Provide previous instance in collection

The function locates the previous instance in a collection starting from the currently located one. When no instance is selected, the function selects the last valid instance.

When a filter has been defined for a collection, the function returns the previous valid instance according to the filter condition.

Notes:

In case of read arrors, the function returns an error, which is difficult to differ fron end of collection. Hence, the more secure way of reading instances in a collection is calling Get(index) and GetCount() in order to determin the size of collection. In case of filter conditions for the collection, one may use GetRelativeCount() and GetAt(index).

Return value:  Return value ( logical  )

The function returns YES when the question was answered positively. Otherwise it returns NO .

Implementation details

logical PropertyHandle  :: Previous ( logical read_opt=YES )
  • read_opt - Read option

    The option forces the function to read the instance when it could be located.

    Default: YES