DROP DOWN app designer

I want to make 3 drop down related between them, when i choose a name from the first it gives me to chose a special names from the second dropdown and then to chose anaother name from the third dropdown

[Adam Danz]

I understand your goal. How could we help you? What have you tried so far? Are you working with App Designer or a different type of GUI? You could create 3 dropdown menus, set the Enable property of the 2nd and 3rd to off, and after the first selection is made, you could populate the 2nd dropdown box with options and enable it. Then repeate for the 3rd dropdown box.

[Rida BOUMEDIANE]

Thanks for the answer, When o will click on the first choice the dropdown2 will give me only the needed items depending on the first drop down, and the same thing for the third dropdown it will depend on the second dropdown. Yes i m using app designer

[Adam Danz]

I understand that. See my questions above.

Answer 1

[Aniket]

Hi @Rida BOUMEDIANE

I understand you want to create interdependent dropdown menus in App Designer, where each selection dynamically determines the options in the next dropdown. This can be accomplished by using callback functions to populate and enable each subsequent dropdown based on the previous selection.

Kindly follow the steps below to achieve this functionality:

1. Initialise the dropdowns

2. Set the "Enable" property of ‘DropDown2’ and ‘DropDown3’ to "off". You may refer to following link to know more about "Enable" property of DropDown UI component:

https://www.mathworks.com/help/matlab/ref/matlab.ui.control.dropdown.html#buh_e24-56_sep_shared-Enable

3. Populate the first dropdown with options.

The startup function should look like this:

function startupFcn(app) 
    app.Dropdown1.Items = fieldnames(data); 
    app.Dropdown2.Enable = 'off'; 
    app.Dropdown3.Enable = 'off'; 
end 

4. Implement a callback function for ‘DropDown1’ that populates options in ‘DropDown2’ based on selection in ‘DropDown1’. Also it should set "Enable" to "on" state for ‘DropDown2’.

Callback for ‘Dropdown1’:

function Dropdown1ValueChanged(app, event) 
    selectedOption = app.Dropdown1.Value; 
    app.Dropdown2.Items = data.(selectedOption).SubOptions; 
    app.Dropdown2.Enable = 'on'; 
    app.Dropdown3.Enable = 'off'; 
end 

5. Follow similar steps for ‘DropDown3’ .

You can learn more about callback functions in App Designer using this documentation:

https://www.mathworks.com/help/matlab/creating_guis/write-callbacks-for-gui-in-app-designer.html

I hope this helps you!