PXAccumulator: Implementation of a Custom PXAccumulator Attribute
When you define a custom accumulator attribute, you typically implement the members that are described in the following sections.
- For reference information on methods and properties that you can use in the PXAccumulator attribute, see PXAccumulatorAttribute Class.
- For an example of implementation of a custom accumulator attribute, see PXAccumulator: To Implement a Custom Accumulator Attribute.
Attribute Constructor
By setting the value of the _SingleRecord field in the constructor to
true, you specify that the system should use single-record update mode. In this
mode, the attribute updates the data record independently from the existing data records and
does not add any restrictions to future data records. In single-record update mode, the
framework generates a specific SQL statement that updates an independent record. By default,
single-record mode is not used.
PrepareInsert() Method
In the overridden PrepareInsert() method, you first have to invoke the base PrepareInsert() method to initialize the collection of columns. If the base PrepareInsert() method returns true, the collection of columns is initialized. Then in the overridden method, you can set restrictions and update policies for specific columns. For details about policies, see the description of the PXDataFieldAssign.AssignBehavior enumeration.
In the PrepareInsert() method, the columns are represented by an object
of the PXAccumulatorCollection class. To
update a value or to set a restriction for a column, you invoke the needed generic method of
the columns collection. You can use the following methods in single-record
mode (that is, when _SingleRecord = true is specified in the attribute
constructor):
columns.Update(): Sets the update policy for the field.columns.Restrict(): Sets the value restriction for the column. The restriction triggers the PXLockViolationException exception, which you should handle in the overridden PersistInserted() method of the attribute.
PersistInserted() Method
If you set any restrictions, you have to override the PersistInserted() method. For details, see PXAccumulator: Implementation of an Update with Restrictions.