The native Wifi API's are a set op native code libary API's NOT a set of
managed API's, so you can't use "using ..." .
To use native API's from C#, you'll need to use PInvoke, that means, you
will need to declare all API's, enums and native structures as  managed
functions and types.

// WlanApi function declarations
[DllImport("Wlanapi.dll")]
static extern int WlanOpenHandle( int clientVersion, IntPtr reserved, out
int negotiatedVersion, out IntPtr clientHandle);

// usage
...
int clientVersion = 1; // XP SP2
int negotiatedVersion;
IntPtr clientHandle;
int error = WlanOpenHandle(clientVersion, IntPtr.Zero, out
negotiatedVersion, out clientHandle);
if(error != 0)
{
   // function failed... inspect error number and throw
}
else
{
  // use valid clientHandle in the other wlan API's, like WlanGetProfile,
WlanConnect etc....
...

Willy.