I want to create a vpn application such as "Touch VPN" or "Hi VPN'
How to use xamarin to connect to vpn server using .open files in the background?
There are several example source codes in Java But I never found any source code in xamarin c#
How can I use c# for that purpose?
Please see example Xamarin.Android VPN service demo: https://github.com/luqmanhussain/XamarinAndroidVPNExample
Accodring to your several examples, you can convert java to C# code as well. There are some tips when you want to do that. https://docs.microsoft.com/en-us/xamarin/android/get-started/java-developers
It depends on which protocol you need. But if you need a custom protocol or want to develop your own protocol in .NET using Xamarin, you can see our VpnHood project, a component base VPN via NuGet packages. It is in C# and uses Xamarin to develop the client for Android.
