I installed the google api 3 and the OAuth2. And i tried the google develope example:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

using Google.GData.Client;
using Google.GData.Extensions;
using Google.GData.YouTube;
using Google.GData.Extensions.MediaRss;
using Google.YouTube;



namespace Youtube_Manager
{
    public partial class Form1 : Form
    {
        string devKey = "mykey";
        string userName = "my gmail as login";
        string Password = "mypass";
        string feedUrl = "https://gdata.youtube.com/feeds/api/users/default/playlists?v=2";
        YouTubeRequestSettings settings;

        public Form1()
        {
            InitializeComponent();

            settings = new YouTubeRequestSettings("Youtube Uploader", devKey);
            YouTubeRequest request = new YouTubeRequest(settings);

            Feed<Video> videoFeed = request.Get<Video>(new Uri(feedUrl));
            printVideoFeed(videoFeed);


        }

        static string auth;
        static void printVideoFeed(Feed<Video> feed)
        {
            foreach (Video entry in feed.Entries)
            {
                auth = entry.Author;
            }
        }

        private void Form1_Load(object sender, EventArgs e)
        {

        }
    }
}

The first problem is that the link https://gdata.youtube.com/feeds/api/users/default/playlists?v=2 require loging and password i think when trying to browse to this link i'm getting:

User authentication required. Error 401

The second problem is i'm not sure i'm using the right key. My application name is Youtube Uploader so i went to the google console at: https://console.developers.google.com

There on the left i clicked on apis and enabled: youtube data api v3 And also enabled YouTube Analytics API

Then i clicked on Credentials and i created keys for OAuth so i have now client id key email address key and Certificate fingerprints

Then under it i created public api access and i have Api key.

Then i went to this site start with: https://code.google.com/apis/youtube/dashboard/gwt/index.html#product

And there i see my Developer Key and i didn't use it yet in my csharp code.

Now i want to do first thing just to get a list of my own videos i have uploaded to youtube using my today/current log in and password in this case under the name Daniel Lipman and when i log in i'm using my gmail [email protected] I have some videos i added some years ago.

So the problems are that the link require login and password. And not sure how to use my developer key username and password in my code.

I forgot to mention that only now i found the link with my developer key untill now i tried to use as devKey my client ID key and i guess i was wrong. Now i found my developer key long key.

EDIT

I tried now this:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.IO;
using System.Reflection;
using System.Threading;

using Google.Apis.Auth.OAuth2;
using Google.Apis.Services;
using Google.Apis.Upload;
using Google.Apis.Util.Store;
using Google.Apis.YouTube.v3;
using Google.Apis.YouTube.v3.Data;

using Google.GData.Client;
using Google.GData.Extensions;
using Google.GData.Extensions.MediaRss;

namespace Youtube_Manager
{
    public partial class Form1 : Form
    {
        List<string> results = new List<string>();
        string devKey = "dev key";
        string apiKey = "api key";
        string userName = "my gmail address";
        string Password = "pass";

        public Form1()
        {
            InitializeComponent();

            Run();


        }

        private async Task Run()
        {
            UserCredential credential;
            using (var stream = new FileStream("client_secrets.json", FileMode.Open, FileAccess.Read))
            {
                credential = await GoogleWebAuthorizationBroker.AuthorizeAsync(
                    GoogleClientSecrets.Load(stream).Secrets,
                    // This OAuth 2.0 access scope allows for read-only access to the authenticated 
                    // user's account, but not other types of account access.
                    new[] { YouTubeService.Scope.YoutubeReadonly },
                    "user",
                    CancellationToken.None,
                    new FileDataStore(this.GetType().ToString())
                );
            }

            var youtubeService = new YouTubeService(new BaseClientService.Initializer()
            {
                HttpClientInitializer = credential,
                ApplicationName = this.GetType().ToString()
            });

            var channelsListRequest = youtubeService.Channels.List("contentDetails");
            channelsListRequest.Mine = true;

            // Retrieve the contentDetails part of the channel resource for the authenticated user's channel.
            var channelsListResponse = await channelsListRequest.ExecuteAsync();

            foreach (var channel in channelsListResponse.Items)
            {
                // From the API response, extract the playlist ID that identifies the list
                // of videos uploaded to the authenticated user's channel.
                var uploadsListId = channel.ContentDetails.RelatedPlaylists.Uploads;

                Console.WriteLine("Videos in list {0}", uploadsListId);

                var nextPageToken = "";
                while (nextPageToken != null)
                {
                    var playlistItemsListRequest = youtubeService.PlaylistItems.List("snippet");
                    playlistItemsListRequest.PlaylistId = uploadsListId;
                    playlistItemsListRequest.MaxResults = 50;
                    playlistItemsListRequest.PageToken = nextPageToken;

                    // Retrieve the list of videos uploaded to the authenticated user's channel.
                    var playlistItemsListResponse = await playlistItemsListRequest.ExecuteAsync();

                    foreach (var playlistItem in playlistItemsListResponse.Items)
                    {
                        // Print information about each video.
                        //Console.WriteLine("{0} ({1})", playlistItem.Snippet.Title, playlistItem.Snippet.ResourceId.VideoId);
                        results.Add(playlistItem.Snippet.Title);
                    }

                    nextPageToken = playlistItemsListResponse.NextPageToken;
                }
            }
        }

        private void Form1_Load(object sender, EventArgs e)
        {

        }
    }
}

But it dosn't do anything not throwing exceptions or errors. I used a breakpoint on the line:

using (var stream = new FileStream("client_secrets.json", FileMode.Open, FileAccess.Read))

And right after this line nothing happen it's showing the form1 and that's it.

Now in the constructor i changed and did:

this.Run().Wait();

Now i'm getting exception on this line:

this.Run().Wait();

System.AggregateException was unhandled
  HResult=-2146233088
  Message=One or more errors occurred.
  Source=mscorlib
  StackTrace:
       at System.Threading.Tasks.Task.ThrowIfExceptional(Boolean includeTaskCanceledExceptions)
       at System.Threading.Tasks.Task.Wait(Int32 millisecondsTimeout, CancellationToken cancellationToken)
       at System.Threading.Tasks.Task.Wait()
       at Youtube_Manager.Form1..ctor() in d:\C-Sharp\Youtube-Manager\Youtube-Manager\Youtube-Manager\Form1.cs:line 43
       at Youtube_Manager.Program.Main() in d:\C-Sharp\Youtube-Manager\Youtube-Manager\Youtube-Manager\Program.cs:line 19
       at System.AppDomain._nExecuteAssembly(RuntimeAssembly assembly, String[] args)
       at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args)
       at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
       at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
       at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
       at System.Threading.ThreadHelper.ThreadStart()
  InnerException: System.IO.FileNotFoundException
       HResult=-2147024894
       Message=Could not find file 'D:\C-Sharp\Youtube-Manager\Youtube-Manager\Youtube-Manager\bin\Debug\client_secrets.json'.
       Source=mscorlib
       FileName=D:\C-Sharp\Youtube-Manager\Youtube-Manager\Youtube-Manager\bin\Debug\client_secrets.json
       StackTrace:
            at System.IO.__Error.WinIOError(Int32 errorCode, String maybeFullPath)
            at System.IO.FileStream.Init(String path, FileMode mode, FileAccess access, Int32 rights, Boolean useRights, FileShare share, Int32 bufferSize, FileOptions options, SECURITY_ATTRIBUTES secAttrs, String msgPath, Boolean bFromProxy, Boolean useLongPath, Boolean checkHost)
            at System.IO.FileStream..ctor(String path, FileMode mode, FileAccess access)
            at Youtube_Manager.Form1.<Run>d__1.MoveNext() in d:\C-Sharp\Youtube-Manager\Youtube-Manager\Youtube-Manager\Form1.cs:line 51
       InnerException:

Where do i find this file: client_secrets.json is this is the problem ?