用户登录简单后台代码

　　　　 int userflag;
            string strconn = @"Provider=Microsoft.Jet.OLEDB.4.0;Data Source=|DataDirectory|\\BlogSystem.mdb;Persist Security Info=True";
            string strcmd = " SELECT * FROM USER_INFO WHERE USER_NAME = '" + txtusername.Text.Trim() + "' AND USERPWD = '" + txtuserpasswd.Text.Trim() + "'";
            OleDbConnection conn = new OleDbConnection(strconn);
            OleDbCommand cmd = new OleDbCommand(strcmd, conn);
            conn.Open();
            userflag = Convert .ToInt32( cmd.ExecuteScalar());
            if (userflag > 0)
            {

                Response.Write("<script>alert(\"登陆成功！\")</script>");
                Session["userid"] = txtusername.Text;
                Server.Transfer("Default.aspx");
            }
            else
            {
                Response.Write("<script>alert(\"密码错误，登录失败！\")</script>");

            }
            conn.Close();