public System.string DropdownDisplayValueField {get; set;}
For Parameters with a Parameter Dropdown Object, a column from the data object or custom SQL that sets the display value of the parameter for the dropdown selector. This represents the set of values that should be presented to the end user when they are executing or scheduling a report.
The Display Value is also displayed in reports and used in formulas (except in formula filters).
public System.string DropdownDisplayValueField {get; set;}