[JRD!]

function SetIniBool(const Section, Key: String; const Value: Boolean; const Filename: String): Boolean;
function SetIniInt(const Section, Key: String; const Value: Longint; const Filename: String): Boolean;
function SetIniString(const Section, Key, Value, Filename: String): Boolean;

[Setup]
AppName='Write to ini example';
AppVerName=0.0.0.0
CreateAppDir=false
OutputDir=".\"

[ Code ]
const
  INIFILE = 'config.ini';

procedure OnChange(Sender: TObject);
begin
  SetIniString(TControl(Sender).Name, 'Text', TEdit(Sender).Text, ExpandConstant('{src}\') + INIFILE);
end;

procedure OnClick(Sender: TObject);
begin
  SetIniBool(TControl(Sender).Name, 'State', (Sender as TCheckBox).Checked, ExpandConstant('{src}\') + INIFILE);
end;

procedure CancelButtonClick(CurPageID: Integer; var Cancel, Confirm: Boolean);
begin
  Confirm:=False
  Cancel:=True
end;

procedure InitializeWizard();
begin

  with WizardForm do
  begin
    BorderStyle := bsToolWindow;
    Position := poScreenCenter;
    AutoScroll := False;
    ClientWidth := ScaleX(300);
    ClientHeight := ScaleY(100);
    Caption:={#SetupSetting("AppName")};
    InnerNotebook.Hide;
    OuterNotebook.Hide;
  end;

  with TLabel.Create(WizardForm) do
  begin
    Parent := WizardForm;
    SetBounds(5, 8, 40, 15);
    Caption:='Edit1: ';
    Font.Size:=10;
  end;
  
  with TEdit.Create(WizardForm) do
  begin
    Parent := WizardForm;
    SetBounds(50, 5, WizardForm.ClientWidth - 60, 15);
    OnChange:=@OnChange;
    Name:='Edit1';
  end;

  with TLabel.Create(WizardForm) do
  begin
    Parent := WizardForm;
    SetBounds(5, 33, 40, 15);
    Caption:='Edit2: ';
    Font.Size:=10;
  end;

  with TEdit.Create(WizardForm) do
  begin
    Parent := WizardForm;
    SetBounds(50, 30, WizardForm.ClientWidth - 60, 15);
    OnChange:=@OnChange;
    Name:='Edit2';
  end;

  with TCheckBox.Create(WizardForm) do
  begin
    Parent := WizardForm;
    SetBounds(50, 70, 150, 15);
    OnClick:=@OnClick;
    Name:='CheckBox1';
    Checked:=GetIniBool(Name, 'State', false, ExpandConstant('{src}\') + INIFILE);
  end;

  with TCheckBox.Create(WizardForm) do
  begin
    Parent := WizardForm;
    SetBounds(150, 70, 150, 15);
    OnClick:=@OnClick;
    Name:='CheckBox2';
    Checked:=GetIniBool(Name, 'State', false, ExpandConstant('{src}\') + INIFILE);
  end;

end;