Question

I have been using Resource mentioned in App.xaml directly in XAML file like in Windows 8 App

Text="{StaticResource ApplicationName}"

How can I use the same in Windows Phone 8 using ResourceApp.resx file in XAML directly?

Answer 1

As far as I know you cannot use resource file keys and x:Uid in Windows Phone 8 in the same way as in Windows Store apps.
If you want to localize Windows Phone apps, you have to use some kind of ViewModel, in this ViewModel you instantiate the AppResources class and then use this ViewModel as a DataContext of your Page:

public class MainViewModel : ViewModelBase
{
    /// <summary>
    /// Application localized strings
    /// </summary>
    public AppResources Loc
    {
        get { return _loc ?? (_loc = new AppResources()); }
    }
    private AppResources _loc;

    ...
}

You can then access the resources like this:

Text="{Binding Loc.AppName}"

I’d recommend you to watch MVVM Light videos, they’ll teach you how to use localized resources in ViewModel, databinding, and lot more:
http://www.galasoft.ch/mvvmvideo1
http://www.galasoft.ch/mvvmvideo2