Hi!
Here is a codesnippet I use to get filtertype operator from a filter in a DevExpress grid: OperatorKindToStr is used to extract operatorkind from a filter as string and store it in a xml-file. StrToOperatorKind is used to convert back a string from xml to set an operatorkind in a filter.
const
CUSTFILTER_FILTERITEM = 'FilterItem';
function OperatorKindToStr(const aOperatorKind: TcxFilterOperatorKind): string;
begin
Result := 'foEqual';
case aOperatorKind of
foEqual: Result := 'foEqual';
foNotEqual: Result := 'foNotEqual';
foLess: Result := 'foLess';
foLessEqual: Result := 'foLessEqual';
// Plus a boring list of other constants
end;
function StrToOperatorKind(const aOpKindStr: string): TcxFilterOperatorKind;
begin
Result := foEqual;
if aOpKindStr = 'foNotEqual' then
Result := foNotEqual
else if aOpKindStr = 'foLess' then
Result := foLess
else if aOpKindStr = 'foLessEqual' then
Result := foLessEqual
else if aOpKindStr = 'foGreater' then
Result := foGreater
else if aOpKindStr = 'foGreaterEqual' then
Result := foGreaterEqual
// Plus a boring list of other if-else
end;
procedure UseStrToOperatorKind(const aFilterItem: IXmlDomElement);
begin
if aFilterItem.nodeName = CUSTFILTER_FILTERITEM then
begin // It is an FilterItem
vStr := VarToStr(aFilterItem.getAttribute(CUSTFILTER_COLPROP)); // Get the columnname
vOperatorKind := StrToOperatorKind(aFilterItem.getAttribute(CUSTFILTER_ITEMOPERATOR));
end;
procedure UseOperatorKindToStr(const aFilterItem: TcxCustomFilterCriteriaItem);
var
vStr: String;
begin
if Supports(TcxFilterCriteriaItem(aFilterItem).ItemLink, TcxGridColumn, GridCol) then
vStr := OperatorKindToStr(TcxFilterCriteriaItem(aFilterItem).OperatorKind);
end;
Apparently I want the StrToOperatorKind and OperatorKindToStr to be a bit smarter. I have tried GetEnumProp method in VCL TypeInfo but it won't work. So how can I extract the TcxFilterOperatorKind property from a aFilterItem variable to a string and back to a TcxFilterOperatorKind ?