Question

I have a class which inherets handle.
This class manages (among others) a dropdown box, whose callback should call an instance function.
The instance function looks like this:

function dropDownBox_Callback(src, eventData, obj)
    Redraw(obj);
end

I am trying to pass obj as parameter for the callback, as such:

uicontrol(obj.panel,'Style','popupmenu','CallBack', {@dropDownBox_Callback, obj});

However I get the error

Conversion to cell from double is not possible.

Answer 1

Are you sure that the error is coming from {@dropDownBox_Callback, obj}? Seems unlikely given the message text, and it’s certainly supported.

Try the following:

h = uicontrol(obj.panel,'Style','popupmenu');
callbackFcn = {@dropDownBox_Callback, obj};
set(h, 'Callback', callbackFcn)

If there is an error, which line does it occur on?