Basically what I'm trying to do is to get recent tweets from a user and do stuff with them. I'm using Tweetinvi with PIN-based authentication, as described on the website, like this:
// Create a new set of credentials for the application
var appCredentials = new TwitterCredentials("CONSUMER_KEY", "CONSUMER_SECRET");
// Go to the URL so that Twitter authenticates the user and gives him a PIN code
var url = CredentialsCreator.GetAuthorizationURL(appCredentials);
// This line is an example, on how to make the user go on the URL
Process.Start(url);
// Ask the user to enter the pin code given by Twitter
var pinCode = Console.ReadLine();
// With this pin code it is now possible to get the credentials back from Twitter
var userCredentials = CredentialsCreator.GetCredentialsFromVerifierCode(pinCode, appCredentials);
// Use the user credentials in your application
Auth.SetCredentials(userCredentials);
Now the problem is that I have to sign in and connect to Twitter every time I launch my application via browser, which is mildly annoying. I've tried to save my authentication details in a text file (Consumer Key, Consumer Secret, Access Token, Access Token Secret), and then just insert the info into appCredentials and userCredentials, but with no results, as I keep getting TwitterNullCredentialsException. So how do I save my credentials so that I don't have to reconnect on every launch?
I am the main developer of Tweetinvi.
If you store the 4 credentials information you can then reuse them with 2 different solutions :
Auth.SetUserCredentials("CONSUMER_KEY", "CONSUMER_SECRET", "ACCESS_TOKEN", "ACCESS_TOKEN_SECRET");
// OR
var creds = new TwitterCredentials("CONSUMER_KEY", "CONSUMER_SECRET", "ACCESS_TOKEN", "ACCESS_TOKEN_SECRET");
Auth.SetCredentials(creds);
The documentation might help you set up your application : https://github.com/linvi/tweetinvi/wiki/Introduction