User Input to the Dropdown menu in appdesigner

Hi,

I am developing an application where I need to run some .m files. So, I created a dropdown menu (with 4 options say for eg: a,b,c,d) which when selected and run opens a directory window to select the corresponding .m file to select and run.

If in case in fututre, if the user wants one more option (eg: e) to be added to the dropdown menu list, I have a provision to write the name for dropdown as e and add that to the dropdown menu and run the model.

But, when I close the app and run the app again, the newly added dropdown menu (e) is not there. I need to store that into the database permanetaly. Any suggestions for this ?

   %% Code to add the new dropdown name to the dropdown list      
app.new = app.EditField2.Value;
    if ~any(ismember(app.DropDown.Items,app.new))
        app.DropDown.Items = [app.DropDown.Items app.new];
    end
%% Code to run the corresponding model
if app.DropDown.Value == app.new
    RunModel5; %% name of .m file
end

I want the Item added to be stored permanentaly and also the RunModel5 into the database. Please help me with this

[Harish M Y]

Hey one more thing, the RunModel5 is the .m file which is also selected byy the user for first time and the RunModel5 is to be stored afterwards.

Answer 1

[Akanksha]

Hey Harish M Y,

The code you provided adds a new item to the dropdown only in memory and does not save the new item or the associated .m file path anywhere permanent like a file or database.That’s the reason when the app is closed and reopened, the dropdown resets to its original state and the newly added item and its .m file are lost.

The following code ensures that previously added items are loaded every time the app starts:

if isfile('modelDatabase.mat') 
    data = load('modelDatabase.mat', 'modelMap'); 
    app.modelMap = data.modelMap; 
    app.DropDown.Items = keys(app.modelMap); 
else 
    app.modelMap = containers.Map; 
end 

Also, to save the new dropdown item and its associated .m file path permanently :

newItem = app.EditField.Value; 
[file, path] = uigetfile('*.m', 'Select the corresponding .m file'); 
if ~isKey(app.modelMap, newItem) 
    app.modelMap(newItem) = fullfile(path, file); 
    app.DropDown.Items = [app.DropDown.Items, newItem]; 
    save('modelDatabase.mat', 'modelMap'); 
end 

To run the .m file associated with the selected dropdown item :

selectedItem = app.DropDown.Value; 
if isKey(app.modelMap, selectedItem) 
    run(app.modelMap(selectedItem)); 
end  

Incorporating these code snippets will ensure the dropdown remains dynamic and retains its state.

Even after closing and reopening the app, the previously added model remains available in the dropdown.

PFA the links for further reference

https://www.mathworks.com/help/matlab/ref/matlab.ui.control.dropdown.html

https://www.mathworks.com/matlabcentral/answers/392042-app-designer-set-the-dropdown-with-variable

Hope this helps!