When using listdlg, what is the value assigned when the user exits without making a selection?

I'm using listdlg to give the user a dropdown list to make a selection of. While debugging, I tried exiting the listdlg without making a selection, and I got an error.

I tried to validate the data underneath by using a while loop. Normally when a user exits a menu without making a selection, the variable is assigned to 0. My error is occurring almost 90 lines later, so as long as the data is validated, there shouldn't be any errors.

choice = listdlg("PromptString",{"Select a plant to learn more about."},"SelectionMode","single","ListString",CP);

while choice == 0 % forces user to make selection

choice = listdlg("PromptString",{"Select a plant to learn more about."},"SelectionMode","single","ListString",CP);

end

Since my while loop is just bypassed if the user exits without making a selection, that means the variable choice is not 0. If it's not assigned to 0 when the user exits without making a selection, what is the value assigned?

Answer 1

[the cyclist]

Quoting the documentation for listdlg ...

"If the user clicks Cancel, presses Esc, or clicks the close button in the dialog box title bar, then the indx value is returned as an empty array."

So, I think you need

while isempty(choice)

instead of

while choice == 0

[Zachary Holt]

Thanks