how to Pass data in gui

I want to pass data from a popupmenu to a pushbutton.How can I improve my coding below to effectively pass data from a popup menu to a button by using setappdata and getappdata so that it can either use value in case 1 or case 2.The popup menu gets data from another pushbutton

function popupmenu1_Callback(hObject, eventdata, handles) contents =get(hObject,'Value');

switch contents case 1 % User selected the first item to=getappdata(handles.pushbutton11,'img'); setappdata(handles.pushbutton11,'img',to); case 2 % User selected the second item to=getappdata(handles.pushbutton10,'img'); setappdata(handles.pushbutton10,'img',to); end

function pushbutton10_Callback(hObject, eventdata, handles) tod=getappdata(handles.pushbutton10,'img'); tod=getappdata(handles.pushbutton11,'img'); n=((b * y)+(a * z)+(c*x)+(d * w)+(e*v)+(f*u)); %these are number already defined det=((((1+ (g/100)).^h)-1)/(g/100)); CNesa=(n*365* det);

SNf=((((CNesa/((1/R)*(10^-0.83)*(tod^1.395)))^0.1068)-1)*25.4); set(handles.SN,'String',SNf);