Non-Existent Field When Reading Number from GUI

I'm trying to create a GUI that will read in a value that the user inputs. This is what I have inputted for the to read from the GUI:

function Failure_Box_Callback(hObject, eventdata, handles)

r = str2double(get(handles.Failure_Box,'String'));

The user is prompted to input a value in the Failure Box in the "Edit Text" format in the GUI I have created. There are equations that use r as an input. I get the error "Reference to non-existent field 'Failure_Box'."

This is clearly being defined, but it is not reading it in that format. What can I do to fix this?

Answer 1

[Walter Roberson]

http://matlab.wikia.com/wiki/FAQ#How_can_I_share_data_between_callback_functions_in_my_GUI.3F