Firemonkey (Delphi) TListbox with MultiSelect getting selected items

Question

I'm using Firemonkey in Delphi 10.2 Tokyo.

I have an HD Form with a TListBox with its MultiSelectStyle set to either Extended or Default.

I am able to select multiple items, however I can't find a way to programmatically determine which items are selected.

This code

for loop := 0 to Listbox1.Count - 1 do
if Listbox1.Selected[loop] then ; //Do Something

that I've seen variations of does not compile:

[dcc32 Error] MainApplication.pas(60): E2149 Class does not have a default property

I've been through the various properties and methods of TListBox and I can't see a way of finding out which items are selected.

Can anyone please lend me a hand on this?

Answer 1

In FireMonkey, the TListBox.Selected property is a pointer to the first selected TListBoxItem object. It is NOT an array of boolean states like it is in VCL. You must have been looking at VCL examples, not FMX examples.

The error message is because you are trying to apply your [loop] index to a specific TListBoxItem object, which does not have a default property.

Use this instead:

for loop := 0 to ListBox1.Count - 1 do
begin
  if ListBox1.ListItems[loop].IsSelected then
    ...
end;