在C#中连接了数据库怎么实现普通用户和管理员登录界面不同

           string UserID = this.username.Text.Trim();
            string UserPwd = this.password.Text.Trim();

            SqlConnection conn = new SqlConnection();
            conn.ConnectionString = "initial Catalog=booksys;Data source=DELL4-330338\\SQLEXPRESS;integrated Security=SSPI";
            conn.Open();         
            SqlCommand cmd = new SqlCommand();
            cmd.Connection = conn;
             = CommandType.Text;
            "select * from userinfo where UName='"+UserID+"' and UPwd='"+UserPwd+"'";
            SqlDataReader dr;
            dr =cmd.ExecuteReader();
             if
                (dr.Read())
            {
                if (Form1.username.Equals(username) && user.Upwd.Equals(password))
                 {
                     if (comboBox1. == 1)
                     {
                         MessageBox.Show("欢迎管理员" + username + "登陆");
                     }
                     else
                     {
                         MessageBox.Show("欢迎用户" + username + "登陆");

                     }

                Form2 fm = new Form2();
                this.Hide();
                fm.Show();
               
            }
            else{
                this.lbError.Visible=true;
                this.lbError.Text="你输入的用户名或者密码错误，请重新输入！";
            }