popupmenu in GUI gives error when calling a function AND set(handles.text,'string','dense') - but not when using only one of the two

Question

Tania Kleynhans 2017-6-23

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/346043-popupmenu-in-gui-gives-error-when-calling-a-function-and-set-handles-text-string-dense-but-no

评论： Tania Kleynhans 2017-6-23

I have created a GUI with a popupmenu. Only two choices. Choice 1 works well, Choice 2 only works if I take out either row 2 or row 4 in code below. If I leave in all four lines then I get an error - see error below code. Line 3 does not make a difference (if I take it out I just change dense to 'dense'). I am rather stuck as I think this code worked a few days ago.

 function popupmenu1_Callback(hObject, eventdata, handles)
 contents = get(hObject,'Value'); 
 I_bw_tissue=handles.I_bw_tissue;
 I_lessSkin=handles.I_lessSkin;
 I_bw_sml=handles.I_bw_sml;
 if contents == 1
    set(handles.text26,'string', 'N/A');
 elseif contents == 2
    cd 'C:\Users\Documents\Code_Density';                                           [1]
    [total_per, str_dense] = ROI_density(I_bw_tissue,I_lessSkin, I_bw_sml);            [2]
    dense = 'Do not know'     %strcat([str_dense,'; ', num2str(total_per),'%'])        [3]
    set(handles.text26,'string', dense);                                               [4]
end
guidata(hObject,handles)

And the error when having all 4 lines in:

 Error using matlab.ui.control.UIControl/set
Invalid or deleted object.
Error in OpenFolder>popupmenu1_Callback (line 135)
    set(handles.text26,'string', dense);
Error in gui_mainfcn (line 95)
        feval(varargin{:});
Error in OpenFolder (line 42)
    gui_mainfcn(gui_State, varargin{:});
Error in
matlab.graphics.internal.figfile.FigFile/read>@(hObject,eventdata)OpenFolder('popupmenu1_Callback',hObject,eventdata,guidata(hObject)) 
Error while evaluating DestroyedObject Callback

As mentioned, when running this with lines 1,2 and 3, it works, when running with lines 1,3,4 - it works and displays, but not when I run lines 1,2,3 and 4