Simple Shopping Cart

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Introduction

This is a simple basket or shopping cart, that user can select some goods from list and add them to shopping cart. Also a user can remove or change the count of each good. In this article, I use session for storing the shopping cart user can submit for buying and shopping cart saved in database.

Using the Code

In Web, if you need to have common variable in all pages, you must save in session. Session variables store in server and for each user webserver creates a new session ID and session variables. You can store any object in session. I create a DataTable for storing shopping cart and set it in session variable.

Creating a session is very simple:

Session["variable-name"] = variable-value;

Session variable will remove after session time out (default time is 20 minutes), but if you want to remove a session variable:

Session.Remove("variable-name");

In this project, I store DataTable in session. In Page_Load, if there is session variable it reads and if not, it creates an empty DataTable.

if (Session["basket"] != null)
	///read Basket_DataTable from session if exist
	Basket_DataTable = (DataTable)Session["basket"];
else
{
	//create an empty DataTable and Add some columns to it
	Basket_DataTable = new DataTable();
	Basket_DataTable.Columns.Add("id");
	Basket_DataTable.Columns.Add("name");
	Basket_DataTable.Columns.Add("price");
	Basket_DataTable.Columns.Add("pic");
	Basket_DataTable.Columns.Add("count");
	Basket_DataTable.Columns.Add("total");
}

After this, all changes will be made on Basket_DataTable and finally Basket_DataTable saved in session.

Session["basket"] = Basket_DataTable; 

For adding items to shopping cart, I first search for item in Basket_DataTable and if it not found, item will add to shopping cart:

//search item in DataTable
bool Found = false;
for (int i = 0; i < Basket_DataTable.Rows.Count; i++)
    if (Basket_DataTable.Rows[i][0].ToString() == 
    Request["ID"].ToString())
        Found = true;

In the above code, Request["ID"] is ID of Item.

Before adding Item, I search item ID in database and if it finds item, add to basket.

//add item to DataTable
if (Found == false)
{
    //search item in database
    DataAcess data = new DataAcess();
    string sql = "SELECT * FROM kala where id=" + Request["ID"];
    DataTable ret= data.exe_select(sql);
    //if it found in database add it to basket
    if (ret != null && ret.Rows.Count == 1)
    {
        Basket_DataTable.Rows.Add(new object[] 
        { Request["ID"],ret.Rows[0]["name"].ToString()
                                  ,ret.Rows[0]["price"].ToString(),
                                  ret.Rows[0]["pic"].ToString()
                                 ,"1",ret.Rows[0]["price"].ToString()});
    }
}

For removing items from shopping cart, I add a link in each Item that send item id. To remove I search item and if it is found, it will be removed.

if (Request["DelID"] != null)
{
    //search and remove
    for (int i = 0; i < Basket_DataTable.Rows.Count; i++)
        if (Basket_DataTable.Rows[i][0].ToString() == 
        Request["DelID"].ToString())
            Basket_DataTable.Rows.Remove(Basket_DataTable.Rows[i]);
}

Also I add a TextBox for each item, for item count. User can change item count and click update button and item count will change in DataTable.

for (int i = 0; i < GridView2.Rows.Count; i++)
{
    TextBox Tb=(TextBox) GridView2.Rows[i].FindControl("TextBoxCount");
    Basket_DataTable.Rows[i]["count"] = Tb.Text;
    Basket_DataTable.Rows[i]["total"] = Convert.ToInt32(Tb.Text)*
		Convert.ToInt32(Basket_DataTable.Rows[i]["price"]);
}

I also add some code for saving shopping cart in database, I save item id and item count in database.

DataAcess data = new DataAcess();
for (int i = 0; i < GridView2.Rows.Count; i++)
{
	String ID = GridView2.Rows[i].Cells[0].Text.ToString(); ;
	TextBox Tb = (TextBox)GridView2.Rows[i].FindControl("TextBoxCount");
	string sql = "INSERT INTO Basket (count, id)VALUES ({0}, {1})";
	sql = string.Format(sql, Tb.Text, ID);
	data.exe_cmd(sql);
}

Summary

In this article, I describe a simple shopping cart with session. It is simple but I hope it helps you. Also, you can find a simple and useful class for connecting to database (I don't mention in the article).

Have fun with C# coding.

History

• 31^st December, 2010: Initial post