How to update the number of options in a drop-down menu using a slider in App Designer

I am struggling to understand how to update the properties of other components within an app using App Designer; specifically, how would one update the 'Items' vector of a drop-down menu based on the value set by a slider?

[Tommy]

The drop-down menu should be saved as a property. In the below example, it is saved in a property called DropDown. In the slider's ValueChangedFcn, you can then access it with app.DropDown.

classdef app1 < matlab.apps.AppBase

    % Properties that correspond to app components
    properties (Access = public)
        UIFigure       matlab.ui.Figure
        DropDownLabel  matlab.ui.control.Label
        DropDown       matlab.ui.control.DropDown
        SliderLabel    matlab.ui.control.Label
        Slider         matlab.ui.control.Slider
    end

    % Callbacks that handle component events
    methods (Access = private)

        % Value changed function: Slider
        function SliderValueChanged(app, event)
            value = app.Slider.Value;
            app.DropDown.Items = compose('Option %d', 1:(floor(value/20)+1));
        end
    end

    % Component initialization
    methods (Access = private)

        % Create UIFigure and components
        function createComponents(app)

            % Create UIFigure and hide until all components are created
            app.UIFigure = uifigure('Visible', 'off');
            app.UIFigure.Position = [100 100 640 480];
            app.UIFigure.Name = 'UI Figure';

            % Create DropDownLabel
            app.DropDownLabel = uilabel(app.UIFigure);
            app.DropDownLabel.HorizontalAlignment = 'right';
            app.DropDownLabel.Position = [68 319 66 22];
            app.DropDownLabel.Text = 'Drop Down';

            % Create DropDown
            app.DropDown = uidropdown(app.UIFigure);
            app.DropDown.Items = {'Option 1'};
            app.DropDown.Position = [149 319 100 22];

            % Create SliderLabel
            app.SliderLabel = uilabel(app.UIFigure);
            app.SliderLabel.HorizontalAlignment = 'right';
            app.SliderLabel.Position = [322 330 36 22];
            app.SliderLabel.Text = 'Slider';

            % Create Slider
            app.Slider = uislider(app.UIFigure);
            app.Slider.ValueChangedFcn = createCallbackFcn(app, @SliderValueChanged, true);
            app.Slider.Position = [379 339 150 3];

            % Show the figure after all components are created
            app.UIFigure.Visible = 'on';
        end
    end

    % App creation and deletion
    methods (Access = public)

        % Construct app
        function app = app1

            % Create UIFigure and components
            createComponents(app)

            % Register the app with App Designer
            registerApp(app, app.UIFigure)

            if nargout == 0
                clear app
            end
        end

        % Code that executes before app deletion
        function delete(app)

            % Delete UIFigure when app is deleted
            delete(app.UIFigure)
        end
    end
end