Create a checkbox to optionally delete files in a custom page at Inno Setup uninstaller - inno-setup

Question

I created custom pages for an uninstaller using this code: How to create a OuterNotebook/welcome page in the Inno Setup uninstaller? and I want to create a checkbox that allows me to optionally delete certain files in a custom page (before the uninstallation process). I am trying to use this code:
NewCheckBox1 := TNewCheckBox.Create(UninstallProgressForm);
with NewCheckBox1 do
begin
Parent := UninstallfirstPage;
Left := NewStaticText1.Left;
Top := NewStaticText1.Top + NewStaticText1.Height + 8;
Width := NewStaticText1.Width;
Height := ScaleY(30);
Caption := 'Eliminar partidas guardadas';
end;
But I do not know how to link this code to the action of removing the additional folder in the uninstallation.
For example:

Answer 1

Just test a value of the checkbox in the CurUninstallStepChanged event function and call DelTree function eventually.
var
NewCheckBox1: TNewCheckBox; // a global variable
procedure CurUninstallStepChanged(CurUninstallStep: TUninstallStep);
begin
if CurUninstallStep = usUninstall then // or usPostUninstall
begin
if NewCheckBox1.Checked then
begin
Log('Deleting folder');
if DelTree(ExpandConstant('{userappdata}\My Program'), True, True, True) then
begin
Log('Deleted folder');
end
else
begin
MsgBox('Error deleting folder', mbError, MB_OK);
end;
end;
end;
end;