This topic covers the implementation details of TComboProperty.

 

Scope: cComboProperty.pas; class derived from TSL_Property. Prepared from the curated implementation supplied for this review on 2 October 2026.

 

ComboChoice is an integer selection index. The constructor receives both the ordered Choices list and DefVal; their definitions are not included here. DisplayValue is written from Choices[ComboChoice] and is not imported. Do not infer all legal indices from the examples.

 

Notation and shared helper rules: Reading this reference.

 

XML identity and composition

 

No literal rec_type value is emitted directly by the selected routines. A property envelope, an inherited writer or a delegated record can supply its identifying attributes.

 

Inherited implementation: TSL_Property. Follow it when the ordered behavior invokes inherited methods; inherited fields are not repeated as locally owned fields.

 

Exact XML fields and attributes

 

The paths below start at this record or property node. A slash identifies a child element; @ identifies an attribute. Curly braces mark a variable index or expression, not literal XML text. Initial values describe initialization; they do not establish what an omitted individual element does. The Implementation toggle below contains the supplied routines for exact branch order and conversions.

 

ComboChoice

 

XML representation: The text of the ComboChoice element.

 

Reading: Converts the stored text to a number and assigns it to aPropValue.ComboChoice when the record node exists.

 

Writing: Stores the text representation of DataValue.ComboChoice whenever the writer reaches this field.

 

DisplayValue

 

XML representation: The text of the DisplayValue element.

 

Writing: Stores Choices[DataValue.ComboChoice] whenever the writer reaches this field.

 

Import: This routine does not read this field. See the inherited or enclosing implementation where applicable.

 

Initialization and reset values

 

TComboProperty.CreateInit

 

 

This routine also calls inherited Create; Choices.Assign(ComboChoices); self.FillPropEditor; self.FillDisplayValue. See Implementation for their order and any conditional calls.

 

Storage declarations relevant to interpretation

 

These are in-memory member and property types, not a list of mandatory XML children. They retain array bounds, fixed buffers and selector types. The field reference above defines what is actually serialized.

 

 

Implementation details

 

The Implementation toggle contains only TComboProperty methods. Initializers and helpers belonging to other types are identified separately below. Shared XML-helper limitations are explained in Reading this reference.

 

Implementation