求助~~~

 string name=txtusername .Text.Trim ();
            string pass = txtpassword.Text.Trim ();
            String connectionString = "Server=.;database=sampledatabase;uid=sa;";
            String cmdtext = "select * from logon where username='"+name+"' and password='"+pass+"'";
            SqlConnection s1 = new SqlConnection(connectionString);
            s1.Open();
            SqlCommand command = new SqlCommand(cmdtext, s1);
            int a = command.ExecuteNonQuery();
            if (a > 0)
            {
                Response.Redirect("http://www.baidu.com");
            }
            else
            {
                Response.Redirect("http://www.hao123.com");
            }
            s1.Close();
不知道哪里有问题总是去hao123，求高手帮帮