private void button1_Click(object sender, EventArgs e) { UserPreferenceModule upm = new UserPreferenceModule(client); try { upm.Load(); List <PRODUCT> userPreference = upm.GetPreferenceList(); if (userPreference.Count != 0) { FUserPreference fUserpreference = new FUserPreference(); fUserpreference.ProductsList = userPreference; fUserpreference.Upm = upm; fUserpreference.Show(); } } catch (Exception ex) { Console.WriteLine(ex.Message); } }