i found no way but to create a push button
and to use this code
i
% --- Executes on button press in pushbutton1.
function pushbutton1_Callback(hObject, eventdata, handles)
% hObject handle to pushbutton1 (see GCBO)
% eventdata reserved - to be defined in a future version of MATLAB
% handles structure with handles and user data (see GUIDATA)
v = evalin('base','your var name')
set(handles.text1,'String',v);
after executing it, the pushbutton will importe the value or your var to the text box.