Hi,

I know I am going to ask a silly question. But I am fighting with this problem for the last one week and unable to get the result. So please assist me.

I am building a shopping cart project. At a certain point there is a condition that whenever user enters the same product again and again, only the quantity should be updated. I have done that and is working fine.

But the problem is : Suppose I am having a single item in the cart with quantity "1". Whenever I click the browser refresh it automatically increases the quantity of the item.
That is whenever I refresh the page it will update the quantity.

I searched a lot and got the conclusion that:

When page posts, browser keeps the posted data in cache and sends it again when refresh button is pressed. So all the events executed before will get executed again. To avoid this, do a redirect once you added an item to shopping cart. Redirection will clear the post data.

// do shopping cart updation
Response.Redirect("confirmation.aspx")

In confirmation page, you can inform user that the quantity has been updated. Redirecting to same page will work as well.

But I am unable to understand where to apply the redirect.

1        protected void Page_Load(object sender, EventArgs e)
2        {
3            try
4            {
5                HyperLink HLink = (HyperLink)Master.FindControl("HyperLink3");
6                if (HLink != null)
7                {
8                    HLink.Enabled = false;
9                }
10   
11   
12               if (!Page.IsPostBack)
13               {
14                   if (Session["Cart"] == null)
15                   {
16                       Lblmsg.Visible = true;
17                       dt = new DataTable();
18                       dt.Columns.Add("REF", typeof(string));
19                       dt.Columns.Add("Description", typeof(string));
20                       dt.Columns.Add("QTY", typeof(int));
21                       dt.Columns.Add("Price", typeof(float));
22                       dt.Columns.Add("Cost", typeof(float));
23                       get_data();
24                       Session["Cart"] = dt;
25                       
26                   }
27                   else
28                   {
29                       Lblmsg.Visible = false;
30                       dt = (DataTable)Session["Cart"];
31                       get_data();
32                       Session["Cart"] = dt;
33                   }
34               }
35           }
36           catch(Exception ee)
37           {
38               Lblmsg.Text = ee.Message;
39           }
40       }
41   
42       public void get_data()
43       {
44           try
45           {
46               pro_id = Request.QueryString["pr_id"];
47               quanti = Convert.ToInt32(Request.QueryString["quant"]);
48   
49               if (pro_id != null)
50               {
51                   SqlConnection con = new SqlConnection("Server=.; Database=eclsc; Trusted_Connection=yes");
52                   SqlCommand cmd = new SqlCommand();
53                   cmd.Connection = con;
54                   cmd.CommandText = "select ICEMACHINES.product_id,ICEMACHINES.sh_desc,ICEMACHINES.price from ICEMACHINES where ICEMACHINES.product_id LIKE @product_id union select GLASSWARE.product_id,GLASSWARE.sh_desc,GLASSWARE.price from GLASSWARE where GLASSWARE.product_id LIKE @product_id ";
55                   cmd.Parameters.Add("@product_id", SqlDbType.NVarChar, 50).Value = pro_id;
56                   cmd.Connection.Open();
57                   SqlDataReader rdr = cmd.ExecuteReader();
58                   ArrayList arRole1 = new ArrayList();
59   
60                   while (rdr.Read())
61                   {
62                       desc = (rdr["sh_desc"]).ToString();
63                       id = (rdr["product_id"]).ToString();
64                       unitprice = Convert.ToSingle((rdr["price"]));
65                       cost = unitprice * quanti;
66   
67                   }
68                   cmd.Connection.Close();
69   
70                   int dtcount = dt.Rows.Count;
71                   if (dtcount > 0)
72                   {
73                       string dc = dt.Columns[0].ColumnName;
74                       string filter = String.Format("REF LIKE '{0}*'", id);
75                       DataRow[] arrMatchingValues = dt.Select(filter, "REF");
76                       if (arrMatchingValues.Length > 0)
77                       {
78                           DataRow drUpdateMe = arrMatchingValues[0];
79                           int drUpdateQuant = Convert.ToInt32(drUpdateMe["QTY"]);
80                           int quan = quanti + drUpdateQuant;
81                           float cos = unitprice * quan;
82                           drUpdateMe["QTY"] = quan;
83                           drUpdateMe["Cost"] = cos;
84                           dt.AcceptChanges();
85                           Session["data"] = dt;
86                           GridView1.DataSource = dt;
87                           GridView1.DataBind();
88   
89                       }
90                       else
91                       {
92                           DataRow myrow = dt.NewRow();
93                           myrow["REF"] = id;
94                           myrow["Description"] = desc;
95                           myrow["QTY"] = quanti;
96                           myrow["Price"] = unitprice;
97                           myrow["Cost"] = cost;
98                           dt.Rows.Add(myrow);
99                           dt.AcceptChanges();
100                          Session["data"] = dt;
101                          GridView1.DataSource = dt;
102                          GridView1.DataBind();
103                      }
104                  }
105                  else
106                  {
107                      DataRow myrow = dt.NewRow();
108                      myrow["REF"] = id;
109                      myrow["Description"] = desc;
110                      myrow["QTY"] = quanti;
111                      myrow["Price"] = unitprice;
112                      myrow["Cost"] = cost;
113                      dt.Rows.Add(myrow);
114                      dt.AcceptChanges();
115                      Session["data"] = dt;
116                      GridView1.DataSource = dt;
117                      GridView1.DataBind();
118                  }
119  
120              }
121              else
122              {
123                  int a = 1;
124              }
125              total_items = total_items + quanti;
126              total_Price = total_Price + cost;
127              Session["items"] = total_items;
128              Session["value"] = total_Price;
129          }
130          catch(Exception ee)
131          {
132              Lblmsg.Text = ee.Message;
133          }
134          }

 Please check it out and suggest me where to use redirect. I followed these links:

http://blog.andreloker.de/post/2008/06/Post-Redirect-Get.aspx

http://forums.asp.net/t/1120319.aspx


waiting for your response.


cheers
sneha

Seeing through the articles mentioned, the solution to redirect is to have three step process...

Whenever you want to save any data, the updated quantity in your case, you need to save the data to the database and redirect to a different page to get the data...

Still you need to proceed to do any updations, then have a link in the get page to the update page and do the stuff there...

Hi,

you need to redirect after you store the values in sessions.... it may be in your save button..

pls post your full code....