一个购物车的简单实现(多层开发)

 转自  http://www.dotnetbips.com/0D82BC51-AB67-4F5F-AB04-CD461CE5E910.aspx?articleid=280


  今天在老外的网上发现个写的不错的多层实现的构物车...

      代码如下......

     CCookieShoppingCart.cs  //用 cookie

using System;
using System.Web;
using System.Collections;

namespace ShoppingCartGeneric
{
    public class CCookieShoppingCart:IShoppingCart
    {

        public int Add(string cartid, IShoppingCartItem item)
        {
            HttpCookie c=null;
            if(HttpContext.Current.Request.Cookies["shoppingcart"]==null)
                c=new HttpCookie("shoppingcart");
            else
                c=HttpContext.Current.Request.Cookies["shoppingcart"];
            string itemdetails;
            itemdetails=item.ProductID + "|" + item.ProductName + "|" + item.UnitPrice;
            c.Values[item.ProductID.ToString()]=itemdetails;
            HttpContext.Current.Response.Cookies.Add(c);
            return 1;
        }

        public int Remove(string cartid, IShoppingCartItem item)
        {
            HttpCookie c=HttpContext.Current.Request.Cookies["shoppingcart"];
            c.Values.Remove(item.ProductID.ToString());
            HttpContext.Current.Response.Cookies.Add(c);
            return 1;
        }

        public ArrayList GetItems(string cartid)
        {
            HttpCookie c=HttpContext.Current.Request.Cookies["shoppingcart"];
            ArrayList items=new ArrayList();

            for(int i=0;i<c.Values.Count;i++)
            {
                string[] vals=c.Values[i].Split('|');
                CShoppingCartItem item=new CShoppingCartItem();
                item.ProductID=int.Parse(vals[0]);
                item.ProductName=vals[1];
                item.UnitPrice=decimal.Parse(vals[2]);
                item.Quantity=1;

                items.Add(item);
            }
            return items;
        }

    }
}

CDatabaseShoppingCart.cs  //用数据库

using System;
using System.Data;
using System.Data.SqlClient;
using System.Collections;

namespace ShoppingCartGeneric
{
    public class CDatabaseShoppingCart:IShoppingCart
    {
        private static string connstr=@"data source=.\vsdotnet;initial catalog=northwind;user id=sa";

        public int Add(string cartid, IShoppingCartItem item)
        {
            SqlConnection cnn=new SqlConnection(connstr);
            SqlCommand cmd=new SqlCommand();
            cmd.Connection=cnn;
            cmd.CommandText="insert into ShoppingCart_Products(cartid,productid,productname,unitprice,quantity) values(@cartid,@prodid,@prodname,@unitprice,@qty)";

            SqlParameter p1=new SqlParameter("@cartid",cartid);
            SqlParameter p2=new SqlParameter("@prodid",item.ProductID);
            SqlParameter p3=new SqlParameter("@prodname",item.ProductName);
            SqlParameter p4=new SqlParameter("@unitprice",item.UnitPrice);
            SqlParameter p5=new SqlParameter("@qty",item.Quantity);

            cmd.Parameters.Add(p1);
            cmd.Parameters.Add(p2);
            cmd.Parameters.Add(p3);
            cmd.Parameters.Add(p4);
            cmd.Parameters.Add(p5);

            cnn.Open();
            cmd.ExecuteNonQuery();
            cnn.Close();

            return 0;
        }

        public void UpdateQuantity(string cartid,int productid,int newqty)
        {
            SqlConnection cnn=new SqlConnection(connstr);
            SqlCommand cmd=new SqlCommand();
            cmd.Connection=cnn;
            cmd.CommandText="update ShoppingCart_Products set quantity=@qty where cartid=@cartid and productid=@prodid";

            SqlParameter p1=new SqlParameter("@qty",newqty);
            SqlParameter p2=new SqlParameter("@cartid",cartid);
            SqlParameter p3=new SqlParameter("@prodid",productid);

            cmd.Parameters.Add(p1);
            cmd.Parameters.Add(p2);
            cmd.Parameters.Add(p3);

            cnn.Open();
            cmd.ExecuteNonQuery();
            cnn.Close();

        }

        public int Remove(string cartid, IShoppingCartItem item)
        {
            SqlConnection cnn=new SqlConnection(connstr);
            SqlCommand cmd=new SqlCommand();
            cmd.Connection=cnn;
            cmd.CommandText="delete from ShoppingCart_Products where cartid=@cartid and productid=@prodid";

            SqlParameter p1=new SqlParameter("@cartid",cartid);
            SqlParameter p2=new SqlParameter("@prodid",item.ProductID);

            cmd.Parameters.Add(p1);
            cmd.Parameters.Add(p2);

            cnn.Open();

            cmd.ExecuteNonQuery();

            cnn.Close();
            return 0;
        }

        public System.Collections.ArrayList GetItems(string cartid)
        {
            SqlDataAdapter da=new SqlDataAdapter("select * from ShoppingCart_Products where cartid='" + cartid + "'",connstr);
            DataSet ds=new DataSet();
            da.Fill(ds,"shoppingcart");    
            
            ArrayList arr=new ArrayList();
            foreach(DataRow row in ds.Tables[0].Rows)
            {
                CShoppingCartItem item=new CShoppingCartItem();
                item.ProductID=(int)row["productid"];
                item.ProductName=(String)row["productname"];
                item.Quantity=(int)row["quantity"];
                item.UnitPrice=(Decimal)row["unitproce"];
                arr.Add(item);
            }
            return arr;
        }

    }
}

   CSessionShoppingCart.cs //用 session

using System;
using System.Collections;
using System.Web;

namespace ShoppingCartGeneric
{
    /**//// <summary>
    /// Summary description for CSessionShoppingCart.
    /// </summary>
    public class CSessionShoppingCart:IShoppingCart
    {

        public int Add(string cartid, IShoppingCartItem item)
        {
            ArrayList arr;
            if(HttpContext.Current.Session["mycart"]!=null)
            {
                arr=(ArrayList)HttpContext.Current.Session["mycart"];
            }
            else
            {
                arr=new ArrayList();
                HttpContext.Current.Session["mycart"]=arr;
            }
            arr.Add(item);
            return 0;
        }

        public int Remove(string cartid, IShoppingCartItem item)
        {
            ArrayList items=(ArrayList)HttpContext.Current.Session["mycart"];
            for(int i=0;i<items.Count;i++)
            {
                if(((IShoppingCartItem)items[i]).ProductID==item.ProductID)
                {
                    items.RemoveAt(i);
                    break;
                }
            }
            return 0;
        }

        public System.Collections.ArrayList GetItems(string cartid)
        {
            return (ArrayList)HttpContext.Current.Session["mycart"];
        }
    }
}

CShoppingCart.cs  //基类

using System;

namespace ShoppingCartGeneric
{
    public enum CShoppingCartType
    {
        Cookie,Session,Database
    }

    public class CShoppingCart:IShoppingCart
    {
        private IShoppingCart cart=null;

        public CShoppingCart(CShoppingCartType type)
        {
            switch(type)
            {
                case CShoppingCartType.Cookie:
                    cart=new CCookieShoppingCart();
                    break;
                case CShoppingCartType.Session:
                    cart=new CSessionShoppingCart();
                    break;
                case CShoppingCartType.Database:
                    cart=new CDatabaseShoppingCart();
                    break;
            }
        }

        public int Add(string cartid, IShoppingCartItem item)
        {
            return cart.Add(cartid,item);
        }

        public int Remove(string cartid, IShoppingCartItem item)
        {
            return cart.Remove(cartid,item);
        }

        public System.Collections.ArrayList GetItems(string cartid)
        {
            return cart.GetItems(cartid);
        }

    }
}

   IShoppingCart.cs   接口

using System;

namespace ShoppingCartGeneric
{
    public class CShoppingCartItem:IShoppingCartItem
    {
        private int intProductID;
        private string strProductName;
        private decimal decUnitPrice;
        private int intQuantity;

        public int ProductID
        {
            get
            {
                return intProductID;
            }
            set
            {
                intProductID=value;
            }
        }

        public string ProductName
        {
            get
            {
                return strProductName;
            }
            set
            {
                strProductName=value;
            }
        }

        public decimal UnitPrice
        {
            get
            {
                return decUnitPrice;
            }
            set
            {
                decUnitPrice=value;
            }
        }

        public int Quantity
        {
            get
            {
                return intQuantity;
            }
            set
            {
                intQuantity=value;
            }
        }

    }
}

productcatalog.aspx.cs  //调用页 用户选择


cart.Add(Session.SessionID,item);

//这个 Session.SessionID 不知道作者为什么加这个,,在客个基类中都没有调用...
你把它改成其它的.也一样正常执行.......
可能是多用户时用 session 类时,用它作用户判断确定唯一性,可是我查过资料,每个 session 生成时都有一个唯一的  sessionid 啊......清楚的朋友谈谈......

using System;
using System.Collections;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Web;
using System.Web.SessionState;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;
using System.Data.SqlClient;
using System.Security.Principal;

namespace ShoppingCartGeneric
{
    public class WebForm1 : System.Web.UI.Page
    {
        protected System.Web.UI.WebControls.Button Button1;
        protected System.Web.UI.WebControls.DataGrid DataGrid1;
    
        private void Page_Load(object sender, System.EventArgs e)
        {
            if(!Page.IsPostBack)
            {
                BindGrid();
            }
        }


        private void BindGrid()
        {
            SqlDataAdapter da=new SqlDataAdapter("select * from products",@"data source=.\vsdotnet;initial catalog=northwind;user id=sa");
            DataSet ds=new DataSet();
            da.Fill(ds,"products");

            DataGrid1.DataSource=ds;
            DataGrid1.DataBind();
        }

        Web Form Designer generated code#region Web Form Designer generated code
        override protected void OnInit(EventArgs e)
        {
            //
            // CODEGEN: This call is required by the ASP.NET Web Form Designer.
            //
            InitializeComponent();
            base.OnInit(e);
        }
        
        /**//// <summary>
        /// Required method for Designer support - do not modify
        /// the contents of this method with the code editor.
        /// </summary>
        private void InitializeComponent()
        {    
            this.DataGrid1.SelectedIndexChanged += new System.EventHandler(this.DataGrid1_SelectedIndexChanged);
            this.Button1.Click += new System.EventHandler(this.Button1_Click);
            this.Load += new System.EventHandler(this.Page_Load);

        }
        #endregion

        private void DataGrid1_SelectedIndexChanged(object sender, System.EventArgs e)
        {
            CShoppingCart cart=new CShoppingCart(CShoppingCartType.Cookie);
            CShoppingCartItem item=new CShoppingCartItem();
            item.ProductID=int.Parse(DataGrid1.SelectedItem.Cells[1].Text);
            item.ProductName=DataGrid1.SelectedItem.Cells[2].Text;
            item.UnitPrice=decimal.Parse(DataGrid1.SelectedItem.Cells[3].Text);
            item.Quantity=1;
            
            cart.Add(Session.SessionID,item);
        }

        private void Button1_Click(object sender, System.EventArgs e)
        {
            Response.Redirect("cart.aspx");
        }
    }
}

<%@ Page language="c#" Codebehind="productcatalog.aspx.cs" AutoEventWireup="false" Inherits="ShoppingCartGeneric.WebForm1" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" >
<HTML>
    <HEAD>
        <title>WebForm1</title>
        <meta name="GENERATOR" Content="Microsoft Visual Studio .NET 7.1">
        <meta name="CODE_LANGUAGE" Content="C#">
        <meta name="vs_defaultClientScript" content="JavaScript">
        <meta name="vs_targetSchema" content="http://schemas.microsoft.com/intellisense/ie5">
    </HEAD>
    <body MS_POSITIONING="GridLayout">
        <form id="Form1" method="post" runat="server">
            <asp:DataGrid id="DataGrid1" style="Z-INDEX: 101; LEFT: 24px; POSITION: absolute; TOP: 72px" runat="server"
                BorderColor="#CC9966" BorderStyle="None" BorderWidth="1px" BackColor="White" CellPadding="4"
                AutoGenerateColumns="False" Width="448px">
                <SelectedItemStyle Font-Bold="True" ForeColor="#663399" BackColor="#FFCC66"></SelectedItemStyle>
                <ItemStyle ForeColor="#330099" BackColor="White"></ItemStyle>
                <HeaderStyle Font-Bold="True" ForeColor="#FFFFCC" BackColor="#990000"></HeaderStyle>
                <FooterStyle ForeColor="#330099" BackColor="#FFFFCC"></FooterStyle>
                <Columns>
                    <asp:ButtonColumn Text="Select" CommandName="Select"></asp:ButtonColumn>
                    <asp:BoundColumn DataField="productid" HeaderText="Product ID"></asp:BoundColumn>
                    <asp:BoundColumn DataField="productname" HeaderText="Product Name"></asp:BoundColumn>
                    <asp:BoundColumn DataField="unitprice" HeaderText="Unit Price"></asp:BoundColumn>
                    <asp:ButtonColumn Text="Select" CommandName="Select"></asp:ButtonColumn>
                </Columns>
                <PagerStyle HorizontalAlign="Center" ForeColor="#330099" BackColor="#FFFFCC"></PagerStyle>
            </asp:DataGrid><asp:Button id="Button1" style="Z-INDEX: 102; LEFT: 200px; POSITION: absolute; TOP: 32px" runat="server"
                Text="Show Cart"></asp:Button>
        </form>
    </body>
</HTML>

//购物车

using System;
using System.Collections;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Web;
using System.Web.SessionState;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;

namespace ShoppingCartGeneric
{
    /**//// <summary>
    /// Summary description for cart.
    /// </summary>
    public class cart : System.Web.UI.Page
    {
        protected System.Web.UI.WebControls.Button Button1;
        protected System.Web.UI.WebControls.Button Button2;
        protected System.Web.UI.WebControls.Label Label3;
        protected System.Web.UI.WebControls.Label lblAmt;
        protected System.Web.UI.WebControls.DataGrid DataGrid1;
    
        private void Page_Load(object sender, System.EventArgs e)
        {
            if(!Page.IsPostBack)
            {
                FillCartFromSession();
            }
        }

        private void FillCartFromSession()
        {
            CShoppingCart cart=new CShoppingCart(CShoppingCartType.Cookie);
            ArrayList items=(ArrayList)cart.GetItems(Session.SessionID);
            DataGrid1.DataSource=items;
            DataGrid1.DataBind();
            Button1_Click(null,null);
        }

        Web Form Designer generated code#region Web Form Designer generated code
        override protected void OnInit(EventArgs e)
        {
            //
            // CODEGEN: This call is required by the ASP.NET Web Form Designer.
            //
            InitializeComponent();
            base.OnInit(e);
        }
        
        /**//// <summary>
        /// Required method for Designer support - do not modify
        /// the contents of this method with the code editor.
        /// </summary>
        private void InitializeComponent()
        {    
            this.DataGrid1.DeleteCommand += new System.Web.UI.WebControls.DataGridCommandEventHandler(this.DataGrid1_DeleteCommand);
            this.DataGrid1.SelectedIndexChanged += new System.EventHandler(this.DataGrid1_SelectedIndexChanged);
            this.Button1.Click += new System.EventHandler(this.Button1_Click);
            this.Button2.Click += new System.EventHandler(this.Button2_Click);
            this.Load += new System.EventHandler(this.Page_Load);

        }
        #endregion

        private void Button1_Click(object sender, System.EventArgs e)
        {
            decimal total=0;

            try
            {
                foreach(DataGridItem dgi in DataGrid1.Items)
                {
                    if(dgi.ItemType==ListItemType.Item || dgi.ItemType==ListItemType.AlternatingItem)
                    {
                        TextBox t=(TextBox)dgi.Cells[3].Controls[1];
                        int quantity=int.Parse(t.Text);
                        decimal unitprice=Decimal.Parse(dgi.Cells[2].Text);
                        total=total + (unitprice * quantity);

                        //************************
                        //Only for database shopping cart
                        //IShoppingCart cart=new CShoppingCart(CShoppingCartType.Database);
                        //((CDatabaseShoppingCart)cart).UpdateQuantity(Session.SessionID,int.Parse(dgi.Cells[0].Text),quantity);
                        //************************
                    }
                }
            }
            catch
            {
            }

            lblAmt.Text=total.ToString();
        }

        private void Button2_Click(object sender, System.EventArgs e)
        {
            //now you can iterate through cookies collection
            //and DataGrid and get details of all items
            //then add your code here to insert into database
        }

        private void DataGrid1_DeleteCommand(object source, System.Web.UI.WebControls.DataGridCommandEventArgs e)
        {
            CShoppingCart cart=new CShoppingCart(CShoppingCartType.Cookie);
            CShoppingCartItem item=new CShoppingCartItem();
            item.ProductID=int.Parse(e.Item.Cells[0].Text);
            cart.Remove(Session.SessionID,item);
            FillCartFromSession();
        }

        private void DataGrid1_SelectedIndexChanged(object sender, System.EventArgs e)
        {
        
        }
    }
}

<%@ Page language="c#" Codebehind="cart.aspx.cs" AutoEventWireup="false" Inherits="ShoppingCartGeneric.cart" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" >
<HTML>
    <HEAD>
        <title>cart</title>
        <meta name="GENERATOR" Content="Microsoft Visual Studio .NET 7.1">
        <meta name="CODE_LANGUAGE" Content="C#">
        <meta name="vs_defaultClientScript" content="JavaScript">
        <meta name="vs_targetSchema" content="http://schemas.microsoft.com/intellisense/ie5">
    </HEAD>
    <body>
        <form id="Form1" method="post" runat="server">
            <TABLE id="Table1" cellSpacing="1" cellPadding="1" width="100%" border="0">
                <TR>
                    <TD><asp:DataGrid id="DataGrid1" runat="server" BorderColor="#CC9966" BorderStyle="None" BorderWidth="1px"
                            BackColor="White" CellPadding="4" AutoGenerateColumns="False" Width="100%">
                            <SelectedItemStyle Font-Bold="True" ForeColor="#663399" BackColor="#FFCC66"></SelectedItemStyle>
                            <ItemStyle ForeColor="#330099" BackColor="White"></ItemStyle>
                            <HeaderStyle Font-Bold="True" ForeColor="#FFFFCC" BackColor="#990000"></HeaderStyle>
                            <FooterStyle ForeColor="#330099" BackColor="#FFFFCC"></FooterStyle>
                            <Columns>
                                <asp:BoundColumn DataField="productid" HeaderText="Product ID"></asp:BoundColumn>
                                <asp:BoundColumn DataField="productname" HeaderText="Product Name"></asp:BoundColumn>
                                <asp:BoundColumn DataField="unitprice" HeaderText="Unit Price"></asp:BoundColumn>
                                <asp:TemplateColumn HeaderText="Quantity">
                                    <ItemTemplate>
                                        <asp:TextBox id=TextBox2 runat="server" Text='<%# DataBinder.Eval(Container, "DataItem.quantity") %>' Columns="3">
                                        </asp:TextBox>
                                    </ItemTemplate>
                                    <EditItemTemplate>
                                        <asp:TextBox id=TextBox1 runat="server" Text='<%# DataBinder.Eval(Container, "DataItem.quantity") %>'>
                                        </asp:TextBox>
                                    </EditItemTemplate>
                                </asp:TemplateColumn>
                                <asp:ButtonColumn Text="Delete" CommandName="Delete"></asp:ButtonColumn>
                            </Columns>
                            <PagerStyle HorizontalAlign="Center" ForeColor="#330099" BackColor="#FFFFCC"></PagerStyle>
                        </asp:DataGrid></TD>
                </TR>
                <TR>
                    <TD align="center"><asp:Label id="Label3" runat="server" Font-Bold="True">Total Amount :</asp:Label><asp:Label id="lblAmt" runat="server" Font-Bold="True"></asp:Label></TD>
                </TR>
                <TR>
                    <TD align="center"><asp:Button id="Button1" runat="server" Text="Recalculate"></asp:Button></TD>
                </TR>
                <TR>
                    <TD align="center"><asp:Button id="Button2" runat="server" Text="Place Order"></asp:Button></TD>
                </TR>
            </TABLE>
        </form>
    </body>
</HTML>