c#, sql

what's wrong with this code? why i can't create a new user after input all the information in the popup window, database also no updated.
 protected void Create_Click(object sender, EventArgs e)
    {
        using (DataClassesDataContext db = new DataClassesDataContext())
        {
            int a = Int32.Parse(DropDownList1.SelectedValue);
            int b = Int32.Parse(DropDownList2.SelectedValue);

            UserDetail newUser = new UserDetail();
            newUser.UserName = txtUsername1.Text;
            newUser.Password = txtPassword1.Text;
  &n ...