Multilanguage in WPF

Question

Can you recommend a good way to implement a Multilanguage system for a WPF app? The method I'm using right now involves XML, classes and a xaml extension. It Works fine in most of cases, but when I have to deal with dynamic labels or dynamic text in general it require some extra effort. I would like to let the programmer working only in the main problem and forgot the lang issues.

Answer 1

Follow these steps:

1) Place all String fragments in a separate resource file.

Example: StringResources.xaml:

<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:system="clr-namespace:System;assembly=mscorlib">

    <!-- String resource that can be localized -->
    <system:String x:Key="All_Vehicles">All Vehicles</system:String>

</ResourceDictionary>

2) Make copies for each language and add them (translated) to the merged dictionaries. Don't forget to add the country's ISO code to make things easier.

Example App.xaml:

<Application x:Class="WpfStringTables.App"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
StartupUri="Window1.xaml">
    <Application.Resources>
        <ResourceDictionary >
            <ResourceDictionary.MergedDictionaries>
                <ResourceDictionary Source="StringResources.de-DE.xaml" />
                <ResourceDictionary Source="StringResources.nl-NL.xaml" />
                <ResourceDictionary Source="StringResources.xaml" />
            </ResourceDictionary.MergedDictionaries>
        </ResourceDictionary>
    </Application.Resources>
</Application>

The last resource file with strings will be used to replace text parts in code.

3a) Use the text parts from the String table:

Example Window1.xaml:

<Window x:Class="WpfStringTables.Window1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="Window1" Height="300" Width="300">
    <Grid>
        <Button Margin="51,82,108,129" Name="AllVehiclesButton" 
                Content="{StaticResource All_Vehicles}"/>
    </Grid>
</Window>

3b) Load the resource from code (Only use this code if you don't want to set via XAML):

void PageLoad()
{
  string str = FindResource("All_Vehicles").ToString();
}

4) Switch to new culture at start of application:

Codesnippet from App.xaml.cs:

public static void SelectCulture(string culture)    
{      
    if (String.IsNullOrEmpty(culture))
        return;

    //Copy all MergedDictionarys into a auxiliar list.
    var dictionaryList = Application.Current.Resources.MergedDictionaries.ToList();

    //Search for the specified culture.     
    string requestedCulture = string.Format("StringResources.{0}.xaml", culture);
    var resourceDictionary = dictionaryList.
        FirstOrDefault(d => d.Source.OriginalString == requestedCulture);

    if (resourceDictionary == null)
    {
        //If not found, select our default language.             
        requestedCulture = "StringResources.xaml";
        resourceDictionary = dictionaryList.
            FirstOrDefault(d => d.Source.OriginalString == requestedCulture);
    }

    //If we have the requested resource, remove it from the list and place at the end.     
    //Then this language will be our string table to use.      
    if (resourceDictionary != null)
    {
        Application.Current.Resources.MergedDictionaries.Remove(resourceDictionary);
        Application.Current.Resources.MergedDictionaries.Add(resourceDictionary);
    }

    //Inform the threads of the new culture.     
    Thread.CurrentThread.CurrentCulture = new CultureInfo(culture);
    Thread.CurrentThread.CurrentUICulture = new CultureInfo(culture);

}