Get selected value instantly from a listbox without clicking it first

I have a listbox on my gui. When I start the programm the first value in the listbox is selected. But the programm only registers a value when you click it first. So is there a way the programm can start my calculation without having to click the first option in the listbox?

A quick fix is to add the command to the OpeningFcn

listbox_Callback(handles.listbox, [], handles);

The problem is: This fix works fine for one listbox, but I have 3 on my gui. So when i add 3 of these commands to my openingfunction i get the error:

Reference to non-existent field

Any ideas how i can fix it?

Answer 1

[Image Analyst]

As long as you filled up your listbox somehow, either in GUIDE or your OpeningFcn(), you can get any item in it without having to have the user click on one. For example to get the second item in listbox #3:

allItemsInListbox3 = handles.listbox3.String;  % Get all items from listbox3.
itemNumber2 = allItemsInListbox3{2};  % Extract only the second item from listbox3.

[Jan w]

Do you know how i can get the variable of the list value then?

function listbox_runden_stelle_Callback(hObject, eventdata, handles)
contents=cellstr(get(hObject,'String'));
popupmenu_runden_stelle=contents(get(hObject,'Value'));
if (strcmp(popupmenu_runden_stelle,'10'))
    y=1;
elseif (strcmp(popupmenu_runden_stelle,'100'))
    y=2;
end
handles.y=y;
guidata(hObject, handles);

I want the y=1 to be logged in. Thanks :)

[Jan w]

any ideas? sorry if i push but i don't want to get it lost. Hope you understand.

[Image Analyst]

In whatever callback you want, you can get the selected items like this:

selectedItems = handles.listbox_runden_stelle.Value;

[Walter Roberson]

What does it mean to "get the variable of the list value" ?

[Jan w]

I just wanted the value not the string of the listbox. Image Analyst solved my problem. Thanks! :)