We Keep Coding

How to start with the Google API for Gmail?

I want to receive mails from Gmail in my .NET project with Visual Studio 2022.
I've installed all required NuGet Packages, and now I'm searching for a detailed description of this API.
Which classes and methods are available?
I found something at developers.google.com.
But I miss an overview of the classes and methods.
Or what does the API do?
Right now, I'm able to forward the user of my app to allow me the access to Gmail. I receive the "code", but I have to transform it into a "token2".
Do I have to send a HTTP by myself? Why can I not find a .Net function to do that for me?
Sorry for asking, but I'm searching since two hours for the answer...

Gmail API + Google .net client library Nuget Gmail package.
I've installed all required NuGet Packages, and now I'm searching for a detailed description of this API.
A detailed description of the Gmail api and all its methods can be found on Gmail API documentation page. The documentation for the API lists all the methods that can be used and their required parameters and the responses.
As for the NuGet package for Google.Apis.Gmail.v1 there is no documentation for each of the methods related to each of the Google APIs. This library is generated from the discovery doc so there will be a method in the library for each of the methods listed in the Gmail API documentation. It is "assumed" that by consulting the Gmail API documentations you can "Determine" what method in the library you would need to use.
There is an extremally out of date documentation page for API Client Libraries
.NET
which only goes into some detail of the overall usage of the library it self. It does not tell you how to use every method in every api that it supports.
If you can not figure it out by looking at the documentation as mentioned above then, Your best bet would be to check the assembly directly in visual studio this is something that I am able to do in Rider I would be surprised if Visual studio can not do something similar.
If you have a specific question regarding one of the methods and how to use it in the library please open a new question I would be happy to help.
API vs Client library
what does the API do?
The API gives you access to Gmail api. The Gmail NuGet package gives you access to the Gmail api.
Right now, I'm able to forward the user of my app to allow me the access to Gmail. I receive the "code", but I have to transform it into a "token2".
Depending upon which type of application the library should be handling all the authorization for you. You shouldn't need to worry about the authorization code. Let the library do it for you. Please consult Authorization overview
Do I have to send a HTTP by myself? Why can I not find a .Net function to do that for me?
The library will do all this for you.
var results = service.Users.Labels.List("me").Execute
Will return that response to you.
Links
I think you should start with a few simple examples in order to understand how the Google .NET client library helps you interact with the Gmail api.
Gmail quickstart
How to Access Gmail with C# .net

Auth service using Web Api, membership provider, and SQL Server 2012

I am looking to write an auth service using Web Api, and SQL Server for authenticating and authorizing users on my .net site, but ios and Android apps as well. I'm speculating that basic authentication over SSL is the easiest way to go, but I'm pretty new to this whole section of .net. I'm having trouble finding some clear tutorials that explain how to write such a service. Can anyone point me to some resources on how to do this? I'd appreciate it.

I think you need to look OAuth implementation in .NET.
Here is a video to give you some background on Web API security.
I also suggest getting a trial subscription to Pluralsight training and check out the courses on Web API security.
You may want to target the latest release of Web API 2.0 from Microsoft, it has the most features you'll need.

I think this might be useful for you:
http://www.asp.net/web-api/overview/security/authentication-and-authorization-in-aspnet-web-api

Need Google Talk API for C#.Net

Any one know Google Talk Api for C#.Net?, Please help.

Check out Google Talk for Developers.
It uses the Extensible Messaging and Presence Protocol (XMPP) (Originally called Jabber as #kbok mentioned).
There are numerous XMPP libraries available for .NET. The agsXMPP SDK .NET library being one of them.
Here's a tutorial in C# to get you started:
Google Talk (GTalk) Autoreply using .NET

Google Chat uses the Jabber(AKA XMPP) protocol behind the hood. You can find a .NET binding here : http://code.google.com/p/jabber-net/

This project uses Jabber.net to access Google Chat. That should get you started.

Communication between Windows Form Application and Web Page in C#

I am developing a windows based application using C#.
This should be used by the customer after some verification.
Every time they enter the details, the information should be validated in the server. And based on the response the windows-application should proceed further.
Could you please suggest me some examples or technologies ideal for this scenario?
I read through the documentations about WebClient and HttpWebRequest. But still I am not clear. Sorry I am an Embedded Systems Programmer. I haven't worked on Server related technologies.
Thanks for your help.

I would look at Windows Communication Foundation it is a service and messaging framework designed for exactly what you want to do.

a webservice would be a good solution.
look here for more information on creating a webservice:
http://www.codeproject.com/KB/webservices/myservice.aspx
then you can import your webservice like a reference to a class and use it in your clientside c# programm.
http://www.xefteri.com/articles/show.cfm?id=15
this article is for VB, but it shouldn't be a problem, the important thing is the referencing, which is Visual Studio specific and not VB specific.

I would look at a WCF service using a NetTcpBinding. Here is a good link:
http://msdn.microsoft.com/en-us/magazine/cc163394.aspx
I am a little unsure what your reference to a web page in the post title refers to.

Looking for Oauth Yahoo sample C#

I know threre a lot of libraries dotnetopenauth,oauthbase, etc.
But i need sample of using with yahoo.
Samples,which i find did not work for me.Maybe you have example.Please share :-)
I find bug OauthBase work fine for me :-)

This
one, I found explained very well. And this one is from oAuth official site

Another solution is SocialAuth.NET
This library takes care of all token generation and handshake with Yahoo, Google, Facebook and MSN and expose methods like Login(), GetProfile() and GetContacts(). Infact it also provides option to use its inbuilt authentication engine using which a site with no authentication can be turned authentication enabled with these providers in less than 10 minutes.