Can I use restriction of selections in multiple mode in listdlg?

Hi,

I am using listdlg to list out a file showing multiple currents outputs.

I always need to select only three currents at a time hence need to give restriction in 'SelectionMode' of 3 to avoid user errors.

This is the function I call when I need to do the assignment of the amplifier.

function listboxMIa_Callback(hObject, eventdata, handles)
CurrentArrayLabel = evalin('base', 'CurrentArrayLabel');
[MI_aheader,~] = listdlg('PromptString',{'Select the current outputs for Channel A:' '(Please select a maximum of 3 outputs)'},...
              'Name', 'Amplifier Assignment',...
              'ListSize', [250, 125],...
              'ListString',CurrentArrayLabel);    
assignin('base', 'MI_aheader', MI_aheader);

Is this possible?

Regards,

Varun Jadhav

Answer 1

[TED MOSBY]

Hi,

As of today, listdlg can only do single vs multiple - it cannot limit the number of selections by itself. You have to manually validate the number of selections.

need = 3;
[idx, ok] = listdlg('PromptString', {sprintf('Select exactly %d items:', need)}, ...
                        'SelectionMode','multiple', ...
                        'ListString', CurrentArrayLabel, ...
                        'ListSize', [250 125], ...
                        'Name','Amplifier Assignment');
if ~ok, idx = []; return; end
if numel(idx) == need, return; end
uiwait(warndlg(sprintf('Select exactly %d items (you picked %d).', need, numel(idx)), ...
               'Invalid selection','modal'));

You may contact MathWorks Technical Support if you want this feature to be added!

Hope it helped.