MATLAB: How to switch YLim from auto to manual using contextmenu

axescontextmenuguiuimenu

The following code works OK, switching y limit in Fig3_axes.
    plot_into3=handles.Fig3_axes;
    ylim_menu = uicontextmenu;
    hcb1 = 'set(gco, ''YLimMode'',''auto'')';
    hcb2 = 'set(gco, ''Ylim'',[0,1])';
    uimenu(ylim_menu, 'Label', 'auto', 'Callback', hcb1);
    uimenu(ylim_menu, 'Label', 'manual', 'Callback', hcb2);
    set(plot_into3,'uicontextmenu',ylim_menu);
However, when I try to replace [0,1] by a variable
 Fig3yLim=[0,1];
 hcb2 = 'set(gco, ''Ylim'',Fig3yLim)';
I am getting an error:
Undefined function or variable 'Fig3yLim'.
Error while evaluating uimenu Callback
How can I use the variable?

Best Answer

Yes, of course. Callbacks are evaluated in the base workspace. If you use a variable, which is defined in a function, it is not known when the callback runs.
Better use function for callbacks and store variables in the figure by guidata.
uimenu(ylim_menu, 'Label', 'auto',   'Callback', {@uimenu_Callback, 'auto'});
uimenu(ylim_menu, 'Label', 'manual', 'Callback', {@uimenu_Callback, '01'});
...
function uimenu_Callback(uimenuH, EventData, Command)
handles = guidata(uimenuH);
switch Command
  case '01'
    set(handles.Fig3_axes, 'YLim', [0, 1]);
  case 'auto'
    set(handles.Fig3_axes, 'YLimMode', 'auto');
  otherwise
    error('Unknown command - programming error');
end
Now the contents of the variable Fig3yLim can by added as 4th input argument.
Defining callbacks as strings is supported for backward compatibility with Matlab 5.3 (1999). Using function handles is more secure and efficient.
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