addtocart.aspx.cs

完成一个网上书店系统

using System;
using System.Collections;
using System.Configuration;
using System.Data;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Xml.Linq;
using System.Data.SqlClient;

public partial class AddTOCart : System.Web.UI.Page
{
    Class1 db = new Class1();
    int BookID=-1;
    protected void Page_Load(object sender, EventArgs e)
    {
        BookID = Convert.ToInt32(Request.Params["BookID"]);
        if (!IsPostBack)
        {
            //刷屏竟然也会执行这一步，猜测可能是母版的刷新问题
            ListAddtoCart();

            //返回上一页
            if (Request.UrlReferrer != null)
                ViewState["UrlReferrer"] = Request.UrlReferrer.ToString();

        }
        
    }
    protected void ListAddtoCart()
    {
        //按注销之后，这里不能转换！！！
        int uid = Convert.ToInt32(Session["UserID"]);

        //未完成，分为登录用户和未登录用户
        //未登录用户，可以把书放入购物车，但不能结算，需登录

        String insertstr = null;
        String updatestr = null;
        string sql = null;

        if (Session["UserID"] == null || Session["UserID"].ToString() == "")
        {
            sql = "select * from ShopCart where BookID=" + BookID;
            SqlDataReader dr = db.Reader(sql);
            if (dr.Read())
            {
                updatestr = "update ShopCart set BookCount=BookCount+1,MoneyCount=BookPrice*(BookCount+1),IsCanel='0' where BookID=" + BookID;
                db.ExecSql(updatestr);
            }
            else
            {
                insertstr = "insert into ShopCart( BookID,BookName,BookMarketPrice,BookPrice,ShopDate,BookCount,IsCanel)select BookID,BookName,BookMarketPrice,BookPrice ,GETDATE(),0,0 from Books where BookID= " + BookID;
                updatestr = "update ShopCart set BookCount=BookCount+1,MoneyCount=BookPrice*(BookCount+1),IsCanel='0' where BookID=" + BookID;
                db.ExecSql(insertstr);
                db.ExecSql(updatestr);
            }
             
        }
        else
        {   
            sql = "select * from ShopCart where  UserID=" + uid + " and BookID=" + BookID;
            SqlDataReader dr1 = db.Reader(sql);
            if (dr1.Read())
            {
                updatestr = "update ShopCart set BookCount=BookCount+1,MoneyCount=BookPrice*(BookCount+1),IsCanel='0' where UserID=" + uid + " and BookID=" + BookID;
                db.ExecSql(updatestr);
            }
            else
            {
                 insertstr = "insert into ShopCart( BookID,BookName,BookMarketPrice,BookPrice,ShopDate,BookCount,IsCanel,UserID)select BookID,BookName,BookMarketPrice,BookPrice ,GETDATE(),0,0,UserID from Books,Users where UserID=" + uid + " and BookID= " + BookID;
                 updatestr = "update ShopCart set BookCount=BookCount+1,MoneyCount=BookPrice*(BookCount+1),IsCanel='0' where UserID=" + uid + " and BookID=" + BookID;
                 db.ExecSql(insertstr);
                 db.ExecSql(updatestr);
            }
                 
        }
        
      

        //怎么查数据库出错！解决，主要是更新和插入解决好

        SqlDataReader result = db.Reader(sql);
        while (result.Read())
        {
            Label3.Text = Convert.ToString(result.GetInt32(1));
            Label4.Text = result.GetString(2);
            Label5.Text = (result.GetDecimal(3)).ToString();
            Label6.Text = Convert.ToString(result.GetInt32(5));
            Label7.Text = result.GetDecimal(4).ToString();
            Label8.Text = Convert.ToString(result.GetDecimal(7));
        }
    }
    protected void ImageButton1_Click(object sender, ImageClickEventArgs e)
    {//继续购物
        //Response.Redirect("Default.aspx");
        //返回上一页的功能
        Response.Redirect(ViewState["UrlReferrer"].ToString());
    }
    protected void ImageButton2_Click(object sender, ImageClickEventArgs e)
    {//结算
        Response.Redirect("Checkout.aspx");
    }
}