Getting value from a listbox. Error: Cell contents reference from a non-cell array object.

Im trying to get the value selected in a listbox(Temp_listbox) by a callback botton and the listbox contains cells of integers:

string5   = get(handles.Temp_listbox, 'String');%%get cond1
value5    = get(handles.Temp_listbox, 'Value');
cond1 = string5{value5};

But I got the error: Cell contents reference from a non-cell array object.

Any idea about how could be solved? Thanks in advance.

Note: The value of cond1 is used afterwards to find the intersection in an array and plot the data.

[David Sanchez]

Are you sure this error message makes reference to these lines of code? They seem all right and should not yield an error.

[Manuel]

I think so, the error is :

Cell contents reference from a non-cell array object.

Error in GUI_v1>plot1_Callback (line 405)
cond1 = string5{value5};

And in the same callback function I have also similar code but for other listboxs and is working correctly :

string3   = get(handles.listchip_version, 'String');%%get chip version
value3    = get(handles.listchip_version, 'Value');
chip1 = string3{value3};

string4   = get(handles.listtest, 'String');%%get test version
value4    = get(handles.listtest, 'Value');
test1 = string4{value4};

The only different in the cond1 is the content of the listbox which one is a number and not a string value.

Answer 1

[Grzegorz Knor]

I suppose that your listbox contains only one string. Compare two codes:

1:

lb = uicontrol('Style','listbox','Position',[10 10 100 100],'String','a');
a = get(lb,'String');
a{get(lb,'Value')}

2:

lb = uicontrol('Style','listbox','Position',[10 10 100 100],'String',{'a','b','c'});
a = get(lb,'String');
a{get(lb,'Value')}

Code 1 produces an error.

[Image Analyst]

Exactly what I was going to say. I remember one version of MATLAB a couple of years back where it seemed to return a string if there was only one item in the listbox but a cell array if there were more than 1 item. I haven't encountered this in a while so I don't know if they "fixed" that or if I just haven't been using listboxes with one item in them anymore.

[Walter Roberson]

Also watch out for the case where the String property is empty.

If you are not absolutely positive that the String property will be cell array, then cellstr(get(TheHandle, 'String'))

At one point in an old Answer, I listed the conditions under which the String property would not be a cell array.

[Manuel]

Hello Walter, you are right when the string property is empty does not work, with

 cellstr(get(TheHandle, 'String'))

works perfect.

Thank you very much!

Answer 2

[ES]

Not sure, you must be doing something wrong. It works fine,

if true
  eg:
set(handles.listbox1, 'String',{1,2,3,4})% to set set of integers as entries for the list box.

and somewhee else,

string5 = get(handles.listbox1, 'String');%%get cond1 value5 = get(handles.listbox1, 'Value'); cond1 = string5{value5};

output is cond1=1 end

please check..

[Manuel]

I check and the error is still there :

Cell contents reference from a non-cell array object.
Error in GUI_v1>plot1_Callback (line 405)
cond1 = string5{value5};

And in the same callback function I have also similar code but for other listboxs and is working correctly :

string3   = get(handles.listchip_version, 'String');%%get chip version
value3    = get(handles.listchip_version, 'Value');
chip1 = string3{value3};
string4   = get(handles.listtest, 'String');%%get test version
value4    = get(handles.listtest, 'Value');
test1 = string4{value4};

The only different in the cond1 is the content of the listbox which one is a number and not a string value.