Before using this app, please make sure you do the following:

Note:This sample app is just for reference and works great for Chrome and Firefox. IE throws up some javascript errors so it is advisable to test for the specific browser you are working with and make desired desired changes.
Update your Client ID, Client Secret, Redirect Url (found on developer.intuit.com) in web.config
Update your Log file Path in web.config
Each button click flow should be tested by stopping the application and running it again.
QBO API call can be made for/debugged only for C2QB or OpenId(Get App Now) flows.
In actual app you will have only one of these button click implementations. Testing them all at once will result in exceptions.