Components for Delphi and C++ Builder.

good day, I want to tell you or report a situation in the TDBLookupDataEh.GetLookupValue event when the value of the KeyValue variable is an empty string I show the following message "Could not convert variant of type string".
this happens when the table field is empty.

function TDBLookupDataEh.GetLookupValue: Variant;
var
KeyValue: Variant;
begin
Result := Null;
if DataLink.Active and LookupListActive then
begin
DataSetGetFieldValues(DataLink.DataSet, KeyFields, KeyValue);
if LookupCache then
Result := FLookupListCache.ValueOfKey(KeyValue)
else
if (LookupDataSet <> nil) and LookupDataSet.Active then
Result := ListLink.DataSet.Lookup(LookupKeyFieldNames, KeyValue, LookupDisplayFieldName);
end;
I have marked it in bold so you can see the line