Strongly typed localized strings in universal apps

Back in the old days when the need for localized string arose, I would add a new string and use AppResources to access the correct string in code.
In Windows Phone application (known today as Windows Phone Silverlight 8.0/8.1) I would do something like this:

public void SomeMethod()
{
    var localizedString1 = AppResources.MyFirstSring;
    var localizedString2 = AppResources.AnotherString;
}

In the new universal apps the story is a bit different:

Only strings are allowed in the resource files (which are .resw instead of .resx)
Using a directory for each supported language (i.e. Strings\en-US\)
Access to localized strings is string based

I can live with the first two (I actually prefer it that way) but I have huge problems with Stringly Typed API calls – it’s easy to get it wrong, and even worse a trivial rename can cause problems that would only show during application run.

Luckily a co-worker of mine has put together a T4 template that fixes this problem (thanks Noam):

<#@ template debug="false" hostspecific="true" language="C#" #>
<#@ assembly name="System.Core" #>
<#@ assembly name="System.Xml" #>
<#@ assembly name="System.Xml.Linq" #>
<#@ import namespace="System.Linq" #>
<#@ import namespace="System.Xml.Linq" #>
<#@ import namespace="System.Text" #>
<#@ import namespace="System.Collections.Generic" #>
<#@ output extension=".cs" #>

<# string str = this.Host.ResolvePath("strings\\en-us\\Resources.resw");
    System.Xml.Linq.XElement resXml = System.Xml.Linq.XElement.Load(str); // Read a data file here. "%aaa%/string/en-us/Resources.resw"
   IEnumerable<XElement> appElement = (from dataElements in resXml.Descendants("data") select dataElements); #>

using Windows.ApplicationModel.Resources;

namespace UniversalApp
{
    public class StringsResourceManager
    {
        private static readonly ResourceLoader _resourceLoader = new ResourceLoader();
        public StringsResourceManager()
        {
        }

<# foreach (var element in appElement) { #>  
        public static string <#= element.Attribute("name").Value.Replace(".","_")#>  
        {
            get
            {
                return _resourceLoader.GetString("<#= element.Attribute("name").Value#>");
            }
        } 
<# } #>
    }
}

Using the class created from this template I can get from this:

public void SomeMethod()
{
    var resourceLoader = new ResourceLoader();

    var string1 = resourceLoader.GetString("MyFirstSring");
    var string2 = resourceLoader.GetString("AnotherString");
}

To this:

public void SomeMethod() 
{ 
    var string1 = StringsResourceManager.MyFirstSring; 
    var string2 = StringsResourceManager.AnotherString; 
}

Happy coding…

Labels: .NET, C#, T4, Universal Apps