I am working on porting a Windows Phone application to Windows 8 Metro, using the WinRT API. It is a networking app that makes use of sockets on arbitrary ports (different servers use different ports) On the Wp7 platform, I am able to set both requirements and preferences on which network connection type to use when opening up a socket connection. For instance, by default the socket will only connect on WiFi and not the cellular data connection to protect the user from unexpected data use, but the user can not only set it to use the cellular connection, but to use it even if they are connected to wifi. This is useful for instance if the user is on a corporate network behind a firewall using a wifi connection, but the server or port they want to connect to is blocked by the corporate firewall. In this case, the user can tell my app to use the cellular data connection even while connected to WiFi, so that the connection can go through.
So far, on WinRT, I have only been able to get information about the currently active internet connection, and to enumerate through each connection. I don’t know, however, how to tell a StreamSocket to prefer connecting via an alternate data connection from the currently active one or if this is even possible. Without this capability, the network firewall scenario above will not be possible from the app’s end. The user would have to go to system settings and disable wifi just to work with my app. This is not ideal – my users on Windows Phone love the ability to set this preference without turning wifi on or off.
Is there a method of setting a network adapter preference programatically in WinRT the way it can be done in WP7?
Judging from the (preliminary) documentaion, I don’t believe it’s possible to do this using the standard APIs, without digging deeply into how sockets are instantiated in WinRT – that is, without doing stuff that would get your app disqualified from the Store anyway.
The whole point of the new and redesigned networking APIs is to allows the user (well, and Windows itself) to set the current connectivity options to how the want them, and allow your app to adapt its network usage patterns to the current capabilities of the network.
Arguably, it is a step back from what was available on WP7. But the argument here is to let the system and the user chose what’s more correct at this moment, and have apps adapt to that, instead of having the apps to come up with logic for what network interface to use.