Change the setup language while setup is running (Inno Setup) - inno-setup

Question

How to add the choice of language to the first page, as it is shown in the video?
http://screencast.com/t/SDI5VN67LFL
Thank you all in advance for your help.

Answer 1

Based on the code in this answer, it does what you wanted:
[Setup]
DisableWelcomePage=False
ShowLanguageDialog=no
{...}
[Languages]
Name: "English"; MessagesFile: "compiler:Default.isl"
Name: "French"; MessagesFile: "compiler:Languages\French.isl"
Name: "German"; MessagesFile: "compiler:Languages\German.isl"
Name: "Spanish"; MessagesFile: "compiler:Languages\Spanish.isl"
//Add languages as you like ...
{...}
[Code]
var
LangCombo: TNewComboBox;
SelectLangLabel: TNewStaticText;
LangArray: Array of String;
IsConfirm: Boolean;
function ShellExecute(hwnd: HWND; lpOperation, lpFile, lpParameters, lpDirectory: String; nShowCmd: Integer): THandle;
external 'ShellExecuteW#shell32.dll stdcall';
function IsSetLang: Boolean;
begin
Result := (ExpandConstant('{param:LANG}') = '');
end;
function IsActiveLang: Boolean;
begin
Result := (LangArray[LangCombo.ItemIndex] = ActiveLanguage);
end;
function ActiveLang: Integer;
var
I: Integer;
begin
for I := 0 to (GetArrayLength(LangArray) - 1) do
begin
if (LangArray[I] = ActiveLanguage) then Result := I;
end;
end;
procedure InitializeWizard;
begin
IsConfirm := True;
LangCombo := TNewComboBox.Create(WizardForm);
LangCombo.Parent := WizardForm.WelcomePage;
LangCombo.Top := WizardForm.Bevel.Top - LangCombo.Height - ScaleY(55);
LangCombo.Left := WizardForm.WelcomeLabel1.Left;
LangCombo.Width := WizardForm.WelcomeLabel1.Width;
LangCombo.Style := csDropDownList;
SelectLangLabel := TNewStaticText.Create(WizardForm);
SelectLangLabel.Parent := WizardForm.WelcomePage;
SelectLangLabel.Top := LangCombo.Top - SelectLangLabel.Height - ScaleY(8);
SelectLangLabel.Left := LangCombo.Left;
SelectLangLabel.Caption := SetupMessage(msgSelectLanguageLabel);
LangCombo.Items.Add('English'); //ItemIndex: 0 - English
LangCombo.Items.Add('Français'); //ItemIndex: 1 - French
LangCombo.Items.Add('Deutsch'); //ItemIndex: 2 - German
LangCombo.Items.Add('Español'); //ItemIndex: 3 - Spanish
//Add languages as you like, but make sure the order matches the order of the languages in the array.
SetArrayLength(LangArray,LangCombo.Items.Count);
LangArray[0] := 'English'; //=ItemIndex: 0
LangArray[1] := 'French'; //=ItemIndex: 1
LangArray[2] := 'German'; //=ItemIndex: 2
LangArray[3] := 'Spanish'; //=ItemIndex: 3
//Add languages as you like, but make sure the order matches the order of the languages in the combobox.
LangCombo.ItemIndex := ActiveLang; //set default language as active language
end;
function NextButtonClick(CurPageID: Integer): Boolean;
var
ResultCode: THandle;
begin
Result := True;
if (CurPageID = wpWelcome) and not IsActiveLang then
begin
Result := False;
IsConfirm := False;
ResultCode := ShellExecute(0,'',ExpandConstant('{srcexe}'),'/LANG='+LangArray[LangCombo.ItemIndex],'',SW_SHOW);
if ResultCode <= 32 then MsgBox(Format('Running installer with the selected language failed. Code: %d',[ResultCode]), mbCriticalError, MB_OK);
WizardForm.Close;
end;
end;
function ShouldSkipPage(PageID: Integer): Boolean;
begin
Result := (PageID = wpWelcome) and IsSetLang;
end;
procedure CancelButtonClick(CurPageID: Integer; var Cancel, Confirm: Boolean);
begin
Cancel := True;
Confirm := IsConfirm;
end;
This code demonstrates how to create a language combobox on the WelcomePage, but can of course be replaced with any other or custom page.

Answer 2

Try this:
[Setup]
ShowLanguageDialog=yes
ShowUndisplayableLanguages=yes
[Languages]
Name: "cz"; MessagesFile: "compiler:Languages\Czech.isl";
Name: "de"; MessagesFile: "compiler:Languages\German.isl";
Name: "en"; MessagesFile: "compiler:Default.isl";

Answer 3

You cannot change the language on Inno Setup installer while it is running. The installer on the video must be using some custom build of Inno Setup.
But you can re-start the installer with a new language. See these related questions:
Choosing install language programmatically in Inno Setup
Change the setup language while setup is running (Inno Setup)