Globalization and Localization

Applications must be designed to accommodate users from various cultures. Users in different parts of the world use different languages and different formatting standards for numbers, currency, and dates. International applications should be customizable according to the preferences of users belonging to different nations, cultures, or regions.

An application uses the locale to identify the preference of a user. The local is the combination of a language and a country. For example, the locale of a user speaking English and belonging to the United States is "en-US". The locale includes information about the formats used for representing time and date, symbols and conventions used for representing currency, and the character encoding scheme being used.

The structure of an internationalized application is divided into two blocks:

• Code Block: Contains the application code or the executable part of an application. This block will remain the same for all locales.

• Data Block: Contains all the resources, such as text and images used by the user interface (UI). This block is locale-specific, and each locale will have one data block.

The process of making  an application ready for customers is called internationalization. It includes three phases:

• Globalization: Involves writing the executable code for an application in such a way that makes it culture-neutral and language-neutral. While incorporating globalization, you must ensure that the culture-specific details are not hard-coded into the executable code. The primary task in this phase is to identify the various locale-sensitive resources and to isolate these resources from the executable code.

• Localizability: An application that has been globalized must be tested to ensure that its executable code is independent of the culture and language-specific data. This is called localizability testing. The focus of localizability testing is to check how the application adapts itself to different locales.

• Localization: Involves the customization of an application for a specific locale. One major task in this phase is the translation of resources identified during the globalization phase. During this phase, various resources, such as images and text, for the designated locale are created.

When designing an international application, you should ensure the following factors:

• User Interface (UI): The language used to design different UI components, such as menu, message box, static-text holder (label), is not fixed during design phase of the application.

• Information Formats: The formats of different elements, such as currency, number, and date, are not fixed during design phase of the application.

The different aspects of an application that should be taken into account while incorporating localization are:

• Formats: The formats used for displaying numbers, time, dates and currency should be considered while incorporating localization.

• Graphics: The locale-sensitive graphics, such as maps, traffic signs, and calendar should be considered while incorporating localization.

Implementing Globalization

The System.Globalization namespace provides different classes that enable you to determine locale-specific information, such as te language and country of an application at run time. The System.Globalization namespace includes classes that enable you to localize your application. For example, the Calendar class contains different calendars, such as JulianCalendar and GrgorianCalendar.

Using the CultureInfo Class

Every locale is identified by a culture. The general format of the culture is as follows:

<Language code>-<Country/Region code>

• Language code: Represents a two-letter representation of a language. It is always written in lowercase. For example, the language code for Arabic is "ar" and that for Russian is "ru".

• Country/Region code: Represents a two-letter representation of a country or a region. It is always written in uppercase. For example, the country code for Russia is "RU" and that for France is "FR".

Cultures are of two types:

• Neutral culture: Signifies a culture that is linked only to a language and not to a country. For example, "ru" is a neutral code.

• Specific culture: Signifies a culture that is linked to both a country and a language. For example, "ru-RU" is a specific code.

The following table describes some of the commonly used properties of the CultureInfo class:

The following table describes some of the commonly used methods of the CultureInfo class:

The following code snippet shows how to use the CultureInfo class:

CultureInfo my_CI = new CultureInfo ("ru-RU");

In the preceding code snippet, a new CultureInfo class instance by the name, my_CI, is created that sets the culture of the instance to "ru-RU".

Working with Resources

A resource is any non-executable data that is logically deployed with an application. A resource might be displayed in an application as an error message or as a part of the UI. Examples of resources include the strings displayed in the UI based on the culture settings of the system or a set of images. A separate resource file should be created for each culture for which the application is to be customized. Information is stored in a resource file in the key/value format. For example, to store the welcome message you must assign a the message to a key. Like this:

WelcomeText = "Welcome to my homepage";

In the preceding code snippet, WelcomeText is the key and "Welcome to my homepage" is the value. There are specific naming conventions to follow when naming resource files. The resource file for default culture should be Strings.txt or Strings.ResX, and for any other culture Strings.culture-name.ResX. Where Strings represents the name of the file. For e.g., Strings.fr-CA.resx. After resource files are created in the text form, they need to be converted into a binary format recognized by the .NET Framework.

Generating Resource File

You can use the Resource File Generator (ResGen.exe) command prompt utility to convert a resource file in the text format into the binary format. The syntax is as follows:

resgen [/compile] [inputfilename.extension] [outputfilename.extension]

The extension of the input filename will be .resource.

Creating Resource-Only Assemblies

To create a resource-only assembly, perform the following steps:

1. Create a new Visual C# project with the Empty Project template.

2. From the Project menu, select the Add Existing Item option to add the resources files to the project.

3. In Solution Explorer, right-click your project and select the Properties option. The property page opens.

4. In the Output Type drop-down menu, change the output type of your project to class Library. This will cause your assembly to be compiled as a .dll file.

5. Build you application.

The output will be a DLL file, which will contain all the resource files you added.

Creating Satellite Assemblies

Satellite assemblies are resource-only assemblies that contain only culture-specific resources. The name of the resources included in a satellite assembly should follow this naming convention:

Filename.culture-subculture.resource

The name of a resource file included within a satellite assembly should reflect the culture to which it belongs. All applications will contain one culture-neutral main assembly, which will be loaded by default when a request is sent to the application. The relationship between the main assembly and the satellite assembly under the Windows platform follows a hub-and-spoke model. When a Web application is deployed, the main assembly is always copied in the bin folder in the application root. Satellite assemblies are copied into the subfolders beneath the bin folder in the application root. Satellite assemblies are copied into the subfolders beneath the bin folder based on their culture. For example, the satellite assembly for the culture, fr, will be copied into the bin\fr folder and that for the culture, fr-CA, will be copied into the bin\fr\CA folder.

Perform the following steps to create a satellite assembly:

1. Open the Web application to which you need to add resource files.

2. From the project menu, select the Add existing Item option to add the resource files to your application. Resource files should be named according to the naming conventions.

3. From the Build menu, select the Build solution option to build your solution.

4. Culture-specific resource files are automatically compiled into satellite assemblies and placed in an appropriate directory structure.

The difference between resource-only and satellite assemblies is that resource-only assemblies can contain any resource, such as images and text. Satellite assemblies contain only culture-specific resources.

You can also use the AL.exe utility to link resource files to your application. The AL (Assembly Linker) is a command prompt utility shipped with the standard version of Visual Studio .NET.

Retrieving Resources at Run Time

The System.Resources namespace provides different classes, which enable you to retrieve values from resource files. This namespace contains the ResourceManager class which manages all the resources associated with an application.

ResourceManager Class

It can be used to retrieve resources from an assembly. Each instance of the ResourceManager class is associated with an assembly that contains the resources. This class provides different constructors that can be used according to the need. For example, when you need to retrieve resources from an assembly, use the ResourceManager constructor, which has the following syntax:

ResourceManager ( "BaseName" , "Assembly Name", Type)

In the preceding syntax:

• BaseName: Represents the root name of the resource.

• Assembly Name: Represents the name of the assembly, which contains the resource.

• Type: Represents the ResourceSet, which is the set of resources for a specific culture. The resources associated with each culture have a ResourceSet associated with them.

If the resources are stored in a folder instead of an assembly, you can use the FileBasedResourceManager function of the ResourceManager class. This function takes the following three parameters:

• BaseName: Represents the root of the resource

• ResourceDir: Represents the folder in which the resource is to be searched.

• Type: Represents the ResourceSet.

The other important classes in the System.Resources namespace are:

• ResourceWriter: Used to write into a resource file.

• ResourceReader: Used to read form a resource file.

Configuring a Web application for Globalization

In ASP.NET, you can use the Web.config file to configure an application for globalization. The <globalization> tag enables you to configure locale-specific information, such as culture and encoding. The <globalization> tag has the following attributes:

• requestEncoding: Allows you to specify the assumed encoding of incoming requests. The default value of this attribute is utf-8.

• responseEncoding: Allows you to specify the encoding used for the response data. The default value is utf-8.

• fileEncoding: Allows you to specify the way in which the .aspx, .asmx, .asax files are encoded in a Web application. The default value is utf-8.

• culture: Allows you to specify the culture.

• uiCulture: Allows you to specify the UI culture.

The following code snippet shows an example of how to use the <globalization> tag to configure a Web application:

<globalization
requestEncoding="utf-8"
responseEncoding="utf-8"
culture="ru-RU"
uiculture="ru-RU" />

Practical Demonstration

Here we will be creating an ASP.NET application that is locale-aware. For simplicity sake we our only creating it for 2 cultures, although its just the repetition of steps that would be required if you wish to implement using more cultures.

Our application will have an user interface with a drop down list from where the user can select the culture of his choice and then the Text values of the controls would be as per the selected culture.

Solution:

Perform the following steps for the same:

1. Create a new Web application and I have named it "globalization" as per this example.

2. Change the name of the Webform1.aspx to culture.aspx.

3. Design the culture form. Drag two label controls, a dropdownlist and a button.

4. Create two resource Files. For this right-click the project file and select the Add->New folder. Rename this folder as Resources.

5. Now add new items to this project, select resource assembly file from the template pane. Rename it as strings.resx.

6. In the name column write "msg" and in the value column write "Welcome to my homepage", in this strings.resx file. Save this file and close it.

7. Drag this file to the "Resources" folder from the solution explorer.

8. Similarly add another .resx file, remember to use the culture convention of renaming it. We will be renaming it for France culture so, the it would be renamed as "strings.fr-FR.resx".

9. Now we need to generate strings.Resources file and strings.fr-FR.resources file.For this go to the command prompt of Visual Studio .NET (go to start->all programs->Microsoft Visual Studio .net 2003->Visual Studio .net tools->Microsoft Visual Studio .net command prompt)

10. Type the following command there:  resgen strings.resx

11. Note you will need to navigate to the "Resources" folder using " cd " command of DOS, since you have this .resx file in Resources folder.

12. Do this for all your .resx files and their respective .resources files would be generated, as shown in the figure below:

You can see these files in your Resources folder of your application as shown in the figure.

The main code performing this functionality is given below. You can download example Visual Studio project from this link.

private void Page_Load(object sender, System.EventArgs e)
{
System.Resources.ResourceManager rm =ResourceManager.CreateFileBasedResourceManager( "strings", Server.MapPath("Resources")+Path.DirectorySeparatorChar , null);
string a = Session["lang"].ToString ();
CultureInfo cinfo=new CultureInfo(a);
lblmsg.Text=rm.GetString ("msg",cinfo);
}

Here Session["lang"] is assigned the value of the selected item form the drop down list, that contains the available cultures for the site.

The first output screen looks like this:

When you select any culture, the message is displayed in that particular culture as provided by you in the .resx files (remember the name/value pairs!)

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