Resetting Listbox handle 'value' to prevent warning and dissappearing of listbox on GUI

If I push a button on my GUI to generate an external figure my listbox dissapears on my GUI and I get this warning.

I am recalling setappdata() used elsewhere in the code

Warning: single-selection listbox control requires that Value be an integer within String range
Control will not be rendered until all of its parameter values are valid

The reaseon I get this warning is that on one radio button I import two strings making the handles.listbox3, 'value') = 2 the others it equals '1' If I select the second (bottom) string and change radio button the listbox dissapears because the maximum number of strings sent to the listbox is now 1 and two is outside the bounds. I have tried this at the begining of every point in the switch:

plot_selected = get(handles.listbox3, 'value')
        plots_allowed = get(handles.listbox3, 'string')
        data_2_plot = plots_allowed(plot_selected,:)

or I've tried this

set(handles.listbox3, 'value', 1)

Neither work. Does anyone else have a cleaver way to reset the 'value' handle of the listbox?

Thank you!

[sait]

ind = get(handles.listbox1,'value')

liste = get(handles.listbox1,'String')

liste=cellstr(liste)

liste(ind) = [];

set(handles.listbox1,'String',liste);

set(handles.listbox1,'value',1) % it is purpose to slect first item in listbox

set(handles.listbox1,'visible','on') % if last element of listbox is delete then sometimes listbox is not visible on the gui. For this reason listbox have to update.

Answer 1

[Walter Roberson]

Somehow, the Value of that listbox has become a non-integer (e.g., fraction or []), or become an integer that is not positive, or now exceeds the number of String in the listbox.

[William]

I tried using set(handles.listbox3, 'value',1);

But it does not seem to work. Any suggestions as to how to reset the value of the list box to 1? Thank you!

[Walter Roberson]

Each time you set the String property of the listbox, also set the Value property to 1.

I also recommend you switch away from setting the String property to character arrays, and instead set the String property to a cell array of strings.

set(handles.listbox3, 'String', {'We are the champions', 'of the workd'}, 'Value', 1);

when you retrieve, use

   data_2_plot = plots_allowed{plot_selected};

and then no need to trim trailing blanks off of it.