执行程序不报错，但是登陆进总是连接不上数据库

Question

using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Data.SqlClient;public partial class _Default : System.Web.UI.Page 
{
    protected void Page_Load(object sender, EventArgs e)
    {
        lblUsernameTip.Visible = false;
        lblPasswordTip.Visible = false;
        lblerror.Visible = false;
    }
    private bool PageISVisible()
    {
        if (txtUsername.Text.Trim() != "" && txtPassword.Text.Trim() != "")
            return true;
        else
            return false;
    }
    private void ShowMessage()
    {
        if (txtUsername.Text.Trim() == "")
            lblUsernameTip.Visible = true;
        else
            lblUsernameTip.Visible = false;
        if (txtPassword.Text.Trim() == "")
            lblPasswordTip.Visible = true;
        else
            lblPasswordTip.Visible = false;
    }
    protected void Button1_Click(object sender, EventArgs e)
    {
        if(PageISVisible ())
        {
            string cnstr = "server=.; database=wxpstd; uid=sa; pwd=tjgd";
            SqlConnection ds = new SqlConnection(cnstr);
            ds.Open();
            DataSet dataset1 = new DataSet();
            SqlCommand cmd = new SqlCommand("select * from login where loginid='" + txtUsername.Text.Trim() + "' and password='" + txtPassword.Text.Trim() + "'", ds );
            //SqlDataAdapter cn = new SqlDataAdapter(dataset1, "login");
            //cn.Fill();
            if (cmd.ExecuteNonQuery() > 0)
                {
                    Response.Redirect("welcome.aspx?username=" + txtUsername.Text.Trim());
                }
            else
                {
                    lblerror.Visible = true;
                }
        }
        else
        {
            ShowMessage ();
        }    
    }
}

Answer 1

确定cmd.ExecuteNonQuery() > 0吗？

Answer 2

楼主该恶补基础知识了        SqlCommand cmd = new SqlCommand("select * from login where loginid='" + txtUsername.Text.Trim() + "' and password='" + txtPassword.Text.Trim() + "'", ds ); 
            //SqlDataAdapter cn = new SqlDataAdapter(dataset1, "login"); 
            //cn.Fill(); 
            SqlDataReader reader=cmd.ExeCuteReader();
            if (reader.Read()) 
                { 
                    Response.Redirect("welcome.aspx?username=" + txtUsername.Text.Trim()); 
                } 
            else 
                { 
                    lblerror.Visible = true; 
                }