How to delete the dropdown items permanently using button in app designer

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Harish M Y
Harish M Y 2021-8-5
评论： Harish M Y 2021-8-5
Hi,
I am adding items to dropdown using "ADD button", and stroing those values permanently in appdesigner dropdown items.
Like the same way i need to have a "DELETE button" to delete the selected dropdown item permanently. I tried the below code which deletes the selected item successfullt. However if i close and open the app once again, the perviously deleted item is present .
Properties(access = publix)
new;
end
%% .m file to store the dropdown items into the workspace permanently
dropown = {};
save('dropdown2.mat' , 'dropdown');
%% Appdesigner code
%% Startup function
load('dropdown2.mat');
app.DropDown.Items = dropdown;
%% Add function to add items to dropdown menu and to store those items in dropdown2.mat
app.new = app.EditField.Value;
load("dropdown2.mat");
dropdown(:,end+1) = {app.new};
save("dropdown2.mat","dropdown","-append");
app.DropDown.Items = dropdown;
%% Delete button callback function
[~,idx] = ismember(app.DropDown.Value,app.DropDown.Items);
app.DropDown.Items(idx) = []; %% This delete function call back is deleting the item temporarily. When I re-run the app
%% the deleted item is still present.
%% Please help me to delete the items permanently from dropdown2.mat file also

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采纳的回答

Rik
Rik 2021-8-5
When you delete an element you need to save the mat file again.
You should also consider loading to a struct instead of poofing the variables in the workspace.
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Rik
Rik 2021-8-5
You already show you know how to save a mat file, so here is an example of loading to a struct:
S=load("dropdown2.mat");
dropdown=S.dropdown;
This way it is always clear where variables are coming from.

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