TFPGMapObject.OnKeyCompare
Compare function for key values.
Declaration
Source position: fgl.pp line 393
public property TFPGMapObject.OnKeyCompare : TKeyCompareFunc
read FOnKeyCompare
write SetOnKeyCompare; |
Description
OnKeyCompare can be set to a function that compares key values. The default value for this event is a function that compares keys based on a byte-by-byte comparison of the memory block. The function must have the following semantics:
- Function signature: function(const Key1, Key2: TKey): Integer;
- If the result of this function is negative, the first key (Key1) is assumed to be 'less' than the second key (Key2) and will be moved before the second in the list.
- If the function result is positive, the first key (Key1) pointer is assumed to be 'greater than' the second key (Key2)and will be moved after the second in the list.
- if the function result is zero, the keys are assumed to be 'equal' and no moving will take place.
See also