Jalaj P. Jha Technical & Miscellaneous Ramblings

Changing UI Language during Runtime

This post is subsequent to Phil's comment for creating a user interface where the language can be changed during runtime with a press of a button or so. I had intention to post a detailed post, but due to time contraints posting only a part of it, but hope this would clarify on all steps required to get going.

Let's start with my post VB Forms in Hindi Unicode Fonts. Here I designed a form where all text were in English. As soon as the form was loaded, a text file containing corresponding strings was read and caption/text on each form control was changed to Hindi one.

To achieve UI toggling, why not store the strings read from the file to some array or so and also the corresponding English version to another. Now add a Button "Toggle Language" which would check for the current language (stored in yet another variable), replace all texts with those of the other language, and accordingly change the variable for current Language (mentioned above). Pressing button again would resore the preious UI. The caption of this button can also be changed while changing others.

That should be enough to achieve results.

Now to store the language strings there is a better approach, using a Resource file, which can be created using the VB6 Resource Editor under Tools menu, (You may require to add it through Add-in Manager... under Add-Ins menu)... I kept away from using it as the strings I intended to store were in Hindi Unicode and the Resource Editor doesn't seem to support it... Third Party Tools as Resource Builder can be used for creatign Resource Files with unicode texts. Resource strings as stored above can be read by using LoadResString function available with VB6.

Syntax :
<SomeVariable> = LoadResString (id as long)

The LoadResString function reads from the default string table of the Resource File. There can be additional language/locale specific string tables containing corresponding language/locale strings. In case a string table matching the Regional Settings of the Operating System is found, strings from this table is read instead of the default table.

The above method however does not cater to this specific requirement. However a non-conventional way for storing all language strings in a single table is listed at Load internationalization data from a resource file with a single string table, which can be also be used for this specific purpose.

While LoadResString function available with VB6 doesnot allow you to specify Language/Locale, WinAPI function FindResourceEx, as below, allows you to read language specific strings.

Declare Function FindResourceEx Lib "kernel32.dll" Alias "FindResourceExA" _
        (ByVal hModule As Long, ByVal lpType As Long, ByVal lpName As String, _
        ByVal wLanguage As Long) As Long

Const RT_STRING = 6

For reading from string table the parameter lpType should be RT_STRING as above. The full discussion on this function is out for current scope which I will take up later sometime.