GUI: Saving and loading values edittext boxes

I have a complicated GUI with many "edit text" boxes.

I'd like a quick way to save the value of every single edit text box to a file, and then recall it later (i.e. populate the edit text boxes with the values from the file).

The reason is, I want to make a dropdown with presets. When you click the dropdown and select one of the presets, it loads all the many edittext values from a file. Then you click the dropdown and load a different preset, it loads all the new edittext values from a file.

I can do this manually in the code by grabbing the value from each edittext box and then saving all these to a file, but I'm hoping for a quicker way as there are many edittext boxes and there will be many more added.

I tried the command

guidata

but can't see of a simple 1-line way to do what should be a simple task..

Thanks!