Как выяснить имеет ли объект определённое свойство?
Как выяснить имеет ли объект определённое свойство?
functionhasprop(comp: TComponent; const prop: String): Boolean;
var
proplist: PPropList;
numprops, i: Integer;
begin
result := false;
getmem(proplist, getTypeData(comp.classinfo)^.propcount * Sizeof(Pointer));
try
NumProps := getproplist(comp.classInfo, tkProperties, proplist);
for i := 0 to pred (NumProps) do
begin
if comparetext(proplist[i]^.Name, prop) = 0 then
begin
result := true;
break;
end;
end;
finally
freemem(proplist, getTypeData(comp.classinfo)^.propcount * Sizeof(Pointer));
end;
end;
procedure setcomppropstring(comp: TComponent; const prop, s: String);
var
proplist: PPropList;
numprops, i: Integer;
begin
getmem(proplist, getTypeData(comp.classinfo)^.propcount * Sizeof(Pointer));
try
NumProps := getproplist(comp.classInfo, tkProperties, proplist);
for i := 0 to pred (NumProps) do
begin
if (comparetext(proplist[i]^.Name, prop) = 0) and
(comparetext(proplist[i]^.proptype^.name, 'string') = 0 then
begin
setStrProp(comp, proplist[i], s);
break;
end;
end;
finally
freemem(proplist, getTypeData(comp.classinfo)^.propcount * Sizeof(Pointer));
end;
end;
Взято из
function HasProperty(Obj: TObject; Prop: string): PPropInfo;
begin
Result := GetPropInfo(Obj.ClassInfo, Prop);
end;
procedure TForm1.Button1Click(Sender: TObject);
var
p: pointer;
begin
p := HasProperty(Button1, 'Color');
if p <> nil then
SetOrdProp(Button1, p, clRed)
else
ShowMessage('Button has no color property');
p := HasProperty(Label1, 'Color');
if p <> nil then
SetOrdProp(Label1, p, clRed)
else
ShowMessage('Label has no color property');
p := HasProperty(Label1.Font, 'Color');
if p <> nil then
SetOrdProp(Label1.Font.Color, p, clBlue)
else
ShowMessage('Label.Font has no color property');
end;
