。小弟我的代码在登录时即使输入正确的密码也说密码异常。

求助。。我的代码在登录时即使输入正确的密码也说密码错误。。

using System;
using System.Data;
using System.Configuration;
using System.Collections;
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 login : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {

    }
    protected void Button1_Click(object sender, EventArgs e)
    {
        string userName = TextBox1.Text.ToString().Trim();
        string userPwd = TextBox2.Text.ToString().Trim();
        string userRole = RadioButtonList1.SelectedValue.Trim().ToString();
        string selectStr = "";
        switch (userRole)
        {
            case "0":
                selectStr = "Select * from admin where name ='" + userName + " '";
                break;
            case "1":
                selectStr = "Select * from user where username ='" + userName + " '";
                break;
        }
        SqlConnection conn = new SqlConnection(ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString);
        SqlCommand cmd = new SqlCommand(selectStr, conn);
       
       
        try
        {
            conn.Open();
            SqlDataReader sdr = cmd.ExecuteReader();
            if (sdr.Read())
            {
                if (sdr.GetString(1) == userPwd)
                {
                    Session["userName"] = userName;
                    Session["userRole"] = userRole;
                   conn.Close();
                    switch (userRole)
                    {
                        case "0":
                            Response.Redirect("1.aspx");
                            break;
                        case "1":
                            Response.Redirect("2.aspx");
                            break;
                    }
                }
                else
                    Label1.Text = "密码输入有误";
            }
            else
                Label1.Text = "用户名有误";