ASP.NET购物车实现过程详解

2020-01-17 23:06:56

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1、将test数据库附加到数据库管理系统中；数据库中的book_info包含下列数据：

2、新建一个网站，将images文件夹复制到网站中；
3、在Default.aspx中，通过DataList控件展示数据库中的所有数据，以行为主序，每行3列，单击购买按钮时，将商品的ID和数量保存到HashTable中，并将HashTable放置到Session中。

protected void DataList1_ItemCommand(object source, DataListCommandEventArgs e)   {     string id = e.CommandArgument.ToString();     Hashtable ht;     if (Session["shopcar"] == null)     {       ht = new Hashtable();       ht.Add(id, 1);       Session["shopcar"] = ht;     }     else     {       ht = (Hashtable)Session["shopcar"];       if (ht.Contains(id))       {         int count = int.Parse(ht[id].ToString());         ht[id] = count + 1;         Session["shopcar"] = ht;         Response.Write(count + 1);       }       else       {         ht.Add(id, 1);         Session["shopcar"] = ht;       }     }   }

4、在Default.aspx中添加一个超链接，链接到shopcart.aspx,在shopcart.aspx中显示用户购买的商品信息。
提示：

A、在shopcart中先定义下列变量：

Hashtable ht;  DataTable dt;  string connstring=@"DataSource=./SQLEXPRESS;Initial Catalog=test;Integrated Security=True";  SqlConnection conn;  SqlCommand cmd; SqlDataReader sdr;

B、页面中添加一个GridView。
C、在page_load中，将dt实例化，建立各列。

protected void Page_Load(object sender, EventArgs e)  {    dt = new DataTable();    DataColumn col = new DataColumn();    col.ColumnName= "id";    col.DataType =System.Type.GetType("System.String");    dt.Columns.Add(col);    col = new DataColumn();    col.ColumnName= "name";    col.DataType =System.Type.GetType("System.String");    dt.Columns.Add(col);    col = new DataColumn();    col.ColumnName= "Num";    col.DataType =System.Type.GetType("System.Int32");    dt.Columns.Add(col);    col = new DataColumn();    col.ColumnName= "price";    col.DataType =System.Type.GetType("System.Single");    dt.Columns.Add(col);    col = new DataColumn();    col.ColumnName= "Total";    col.DataType =System.Type.GetType("System.Single");    dt.Columns.Add(col);    if (!IsPostBack)    {      Bind();    }  }    public void Bind()  {         if (Session["shopcar"] == null)    {      Response.Write("<script>if(confirm('你没有登录')window.location='Default15.aspx';else window.close();</script>");    }    else    {      ht = (Hashtable)Session["shopcar"];      foreach (object item in ht.Keys)      {        string id = item.ToString();        int num = int.Parse(ht[item].ToString());        string sql = "selectbook_name,price from book_info where book_id='" + id + "'";        conn = new SqlConnection(connstring);        cmd = new SqlCommand(sql, conn);        conn.Open();        sdr =cmd.ExecuteReader();        if (sdr.HasRows)        {          sdr.Read();          DataRow row = dt.NewRow();          row["id"] = id;          row["Num"] = num;          row["name"] = sdr.GetString(0);          row["price"] =float.Parse(sdr[1].ToString());          row["total"] =num*(float.Parse(sdr[1].ToString()));          dt.Rows.Add(row);        }        sdr.Close();        conn.Close();                     }      GridView1.DataSource = dt.DefaultView;      GridView1.DataBind();    }}

D、这时可以看到用户购买的商品，但不能修改数量，也不能删除。
E、添加修改数量，删除商品功能，在aspx页面中定义GridView中的各列：

 <asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False">     <Columns>       <asp:BoundField DataField="id" HeaderText="ID" />       <asp:BoundField DataField="name" HeaderText="名称" />       <asp:BoundField DataField="price" HeaderText="价格" />       <asp:TemplateField>              <ItemTemplate>         <asp:TextBox runat="server" ID="textbox1" Text='<%# Eval("Num") %>'            ontextchanged="textbox1_TextChanged" AutoPostBack="True" ></asp:TextBox>        </ItemTemplate>             </asp:TemplateField>      <asp:BoundField DataField="total" HeaderText="总计" />      <asp:TemplateField>       <ItemTemplate>        <asp:Button runat="server" ID="button1" CommandArgument='<%# Eval("id") %>'           Text="删除" onclick="button1_Click" />              </ItemTemplate>            </asp:TemplateField>     </Columns>         </asp:GridView>

F、为GridView中的文本框添加TextChanged事件：

protected void textbox1_TextChanged(object sender, EventArgs e)  {        Hashtable ht =(Hashtable)Session["shopcar"];    if (ht == null) return;    for (int i = 0; i < GridView1.Rows.Count;i++)    {      string id =GridView1.Rows[i].Cells[0].Text.ToString();      Response.Write(id);      string num = ((TextBox)GridView1.Rows[i].FindControl("textbox1")).Text;      Response.Write("  "+num+"<br />");      ht[id] = num;    }    Session["shopcar"] = ht;    Bind();     }

G、为按钮添加单击事件：

protected void button1_Click(object sender, EventArgs e)  {    string id = ((Button)sender).CommandArgument;    Hashtable ht = (Hashtable)Session["shopcar"];    if (ht == null) return;    ht.Remove(id);    Bind();}

购物车代码：showcart.aspx.cs

using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.UI; using System.Web.UI.WebControls; using System.Collections; using System.Data; using System.Data.SqlClient;  public partial class shopcart : System.Web.UI.Page {   Hashtable ht;   DataTable dt;   string connstr = "Data Source=.//SQLEXPRESS;AttachDbFilename=F://test.mdf;Integrated Security=True;Connect Timeout=30;User Instance=True";   SqlConnection conn;   SqlCommand cmd;   SqlDataReader sdr;   protected void Page_Load(object sender, EventArgs e)   {     dt = new DataTable();     DataColumn col = new DataColumn();     col.ColumnName = "id";     col.DataType = System.Type.GetType("System.String");     dt.Columns.Add(col);     col = new DataColumn();     col.ColumnName = "name";     col.DataType = System.Type.GetType("System.String");     dt.Columns.Add(col);     col = new DataColumn();     col.ColumnName = "Num";     col.DataType = System.Type.GetType("System.Int32");     dt.Columns.Add(col);     col = new DataColumn();     col.ColumnName = "price";     col.DataType = System.Type.GetType("System.Single");     dt.Columns.Add(col);     col = new DataColumn();     col.ColumnName = "Total";     col.DataType = System.Type.GetType("System.Single");     dt.Columns.Add(col);      if (!IsPostBack)     {       Bind();     }    }    public void Bind()   {     if (Session["shopcar"] == null)     {       Response.Write("<script>if(confirm('你没有登录')window.location='Default.aspx';else window.close();</script>");     }     else     {       ht = (Hashtable)Session["shopcar"];       foreach (object item in ht.Keys)       {         string id = item.ToString();          int num = int.Parse((ht[item].ToString()));         string sql = "select book_name,price from book_info where book_id='" + id + "'";         conn = new SqlConnection(connstr);          cmd = new SqlCommand(sql, conn);         conn.Open();          sdr = cmd.ExecuteReader();         if (sdr.HasRows)         {           sdr.Read();           DataRow row = dt.NewRow();           row["id"] = id;           row["Num"] = num;           row["name"] = sdr.GetString(0);           row["price"] = float.Parse(sdr[1].ToString());           row["total"] = num * (float.Parse(sdr[1].ToString()));           dt.Rows.Add(row);          }         sdr.Close();         conn.Close();       }     }     GridView1.DataSource = dt.DefaultView;     GridView1.DataBind();    }   protected void textbox1_TextChanged(object sender, EventArgs e)   {     Hashtable ht = (Hashtable)Session["shopcar"];     if (ht == null) return;     for (int i = 0; i < GridView1.Rows.Count; i++)     {       string id = GridView1.Rows[i].Cells[0].Text.ToString();       Response.Write(id);       string num = ((TextBox)GridView1.Rows[i].FindControl("textbox1")).Text;       Response.Write("  " + num + "<br />");       ht[id] = num;     }     Session["shopcar"] = ht;     Bind();    }   protected void button1_Click(object sender, EventArgs e)   {     string id = ((Button)sender).CommandArgument;     Hashtable ht = (Hashtable)Session["shopcar"];     if (ht == null) return;     ht.Remove(id);     Bind();    } }

制作一个简单的购物车就是这么简单，大家可以按照我的思路进行创作，在此基础上在添加一些功能。

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