public void OnSaveClicked(object sender, EventArgs args)
 {
     adminDb         = new AdminDb();
     admin.AdminName = txtAdminName.Text;
     admin.Username  = txtUsername.Text;
     admin.Email     = txtEmail.Text;
     admin.Password  = txtPassword.Text;
     adminDb.EditAdmin(admin);
     Navigation.PushAsync(new ManageAdmins());
 }