How to get files by DropBoxRest API in C#

It looks like you're using this library: https://github.com/saguiitay/DropboxRestAPI.

You might consider asking the author for help.

The "authorization code" is generally what gets displayed when you browse to https://www.dropbox.com/1/oauth2/authorize?response_type=code&client_id=<YOUR-APP-KEY>. It looks like AuthorizeAsync returns that kind of URL, so you should then browse to the URL, get the authorization code displayed there, and use it in the next step. (You'd have to prompt the user somehow to enter the authorization code before proceeding.)

This code looks like it might be useful for a command-line app? With a web app, you would use redirects to move the user through the OAuth process (e.g. https://github.com/smarx/othw/tree/master/C%23), and for a desktop app, you would probably display an embedded browser in the app (e.g. https://blogs.dropbox.com/developers/2014/04/dropbox-authorization-in-a-windows-store-app/).

[Cross-linking for reference: https://stackoverflow.com/questions/28833004/how-to-get-dropbox-files-by-dropboxrest-api-in-c ]

There are many libraries in your site for working with DropBox data
My goal is to read dropbox .txt files
Which is the best way to do that ?

Any of the SDKs (ours or third-parties) should be able to read text files from Dropbox.

Now I'm using the following topic
http://www.b4x.com/android/forum/threads/dropbox-oauth-2-tutorial.19503/
It's helpful and I can get information from DropBox but there is a question

Here we need to do a step by hand

var authorizeUrl = "https://www.dropbox.com/1/oauth/authorize?" + queryString;
Process.Start(authorizeUrl);

In above code we have to open browser and click to allow in order can go to the next step.
I don't think that's user friendly. Is there a way to do it without opening the browser.

A user has to grant your application permission before it can access that user's Dropbox. There's no way to do that without the user interacting with dropbox.com (or the Dropbox app on mobile).

But once a user has authorized your app once, they never need to do it again.

Thank you for the answer.
Out project is a desktop application so many users should use the software.
If I get the access_token and Secret can we use it always ? or we need to update access_token after some time ?
Is it right to get access_token and set as static value in code in order software always can use that value for getting an information ?

Once a user has authorized your app (the first time they use it), you should keep reusing the same access token from then on. But you can't hardcode the access token in the app, because it will be different for each user.

Thank you for the answer.
We want to use DropBox as database. All programs should use the same files. So we are going to have a dropbox account and get info from a few softwares. So I think in that case we can hardcode the token, right ?

You could do this, but I would advise against it. Dropbox isn't designed for this kind of account sharing, and anyone who had access to your app would be able to extract the access token and take control of the account (e.g. delete all the files).