GUI Combo Box Update

Hello.
I have a question about how to update a combo box on the GUI.

For example, in my model, I have two options (A and B) for the combo box that update a global variable that effects the processes of the model. By default it shows A because A is the first choice. If I choose B, the code associated with B automatically executes the way I want it to. I run the model and it works fine.

If I close the GUI, and reopen it, the combo box shows A, but the actual variable is still set to B. This said, if I run the model, it looks like it is running A but is actually running B.

How can I make the combo box update its view to the currently defined variable whenever you reopen it?

Also, is it possible to make an 'apply' button so the variables only update whenever I press apply?
Likewise, is it possible to make a 'reset' button that resets the variables (and their displays in the combo boxes) to predefined default values?

Thank you.

For example, in the attached image when "5" is selected for "Number of Registers Open" my model automatically shows 5 registers. If I close the Model Control GUI and open it up again, the combobox shows the default "1" for the "Number of Registers Open," but my model still shows 5 registers. Is there any way to insert a command anywhere so that when the Model Control GUI is opened again, the combobox shows the number of register in the model?

One way:

1. Add an OnOpen attribute to your main GUI object.
2. Write code to determine which listed item the combobox should be pointing to in terms of its rank. For example if your combobox normally sets the value of a global variable, then OnOpen read the current value and determine which item rank in the combobox this value corresponds to. In your case you are lucky that the item value and the item rank are the same.
3. Obtain a reference to the combobox location in the GUI structure
4. Set itemcurrent attribute of the combobox
5. Call comborefresh on the combobox.

In the screenshot below I show 3 different combobox locations, but I skipped step 2 and simply set all itemcurrent to the 3rd item in the list which is "c" in this case.

ex.
treenode combo = node("/combobox1",c);
set(itemcurrent(combo),3);
comborefresh(combo);

In the attached model the GUI is linked to the Model Control button.

Dear Kris Geisberger,
I indeed appreciate your help.
You solved all the problems I had.
Thank you again.