How do I replace the sting value in one popup based on the value selected in another popup?

    popupMenu = uicontrol(topPanel,'Style','popupmenu',...
                'String',solString,...
                'Units','normalized',...
                'Value',1,'Position',[.1 .25 .2 .5],...
                'Callback',@popupmenuCallBack);

    hourpopupMenu = uicontrol(topPanel,'Style','popupmenu',...
                'String',hourString,...
                'Units','normalized',...
                'Value',1,'Position',[.5 .25 .2 .5],...
                'Callback',@hourpopupmenuCallBack);

    function hourpopupmenuCallBack(hObject, eventdata, handles)
        global sol_index_selected
        global hour_index_selected
        global solution_index
        global allData

        hour_index_selected = get(hObject,'Value');

        % to generate new string
        newSolString = [];
        for n=1:size(allData.all_data(hour_index_selected).solutions,1)
            newSolString = [newSolString string("Solution "+n)];
        end

        % NEED TO REPLACE STRING OF "popupmenu" WITH "newSolString"

     end

     % callback function for dropdown/popup menu in the top panel
     function popupmenuCallBack(hObject, eventdata, handles)
         global sol_index_selected
         sol_index_selected = get(hObject,'Value');
     end

Answer 1

[Walter Roberson]

Change

    popupMenu = uicontrol(topPanel,'Style','popupmenu',...
                'String',solString,...
                'Units','normalized',...
                'Value',1,'Position',[.1 .25 .2 .5],...
                'Callback',@popupmenuCallBack);

to

    popupMenu = uicontrol(topPanel,'Style','popupmenu',...
                'String',solString,...
                'Units','normalized',...
                'Value',1,'Position',[.1 .25 .2 .5],...
                'Callback',@popupmenuCallBack, ...
                'tag', 'Pup');

Replace

        newSolString = [];
        for n=1:size(allData.all_data(hour_index_selected).solutions,1)
            newSolString = [newSolString string("Solution "+n)];
        end

with

       newSolString = 'Solution " + (1:size(allData.all_data(hour_index_selected).solutions,1));

       popupmenu = findobj(ancestor(hObject, 'figure'), 'tag', 'Pup');
       popupmenu.String = newSolString;

[Abhay Aradhya]

@Walter

Thank you for the answer. Just inquisitive, can we pass some parameters along with the above callback function? And how do we access the same..

If yes can you please state an example for the same.

[Walter Roberson]

See https://www.mathworks.com/help/matlab/creating_guis/write-callbacks-using-the-programmatic-workflow.html#brqow8p