Partial Class ViewCart
Inherits System.Web.UI.Page

Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
‘ ASP.NET keeps track of the state of all server controls
‘ (like the GridView). Because of this, we don’t need to supply it with
‘ the data every time the page loads. (No more re-checking checkboxes
‘ that were checked or re-selecting the right item in the drop-down when
‘ the page Is submitted. It’s all done for you!)

If Not IsPostBack Then
BindData()
End If
End Sub

Protected Sub BindData()
‘ Let’s give the data to the GridView and let it work!
‘ The GridView will take our cart items one by one and use the properties
‘ that we declared as column names (DataFields)
Dim cart As ShoppingCart = ShoppingCart.GetShoppingCart()
gvShoppingCart.DataSource = cart.Items
gvShoppingCart.DataBind()
End Sub

Protected Sub gvShoppingCart_RowDataBound(ByVal sender As Object, ByVal e As GridViewRowEventArgs) Handles gvShoppingCart.RowDataBound
‘ If we are binding the footer row, let’s add in our total
If e.Row.RowType = DataControlRowType.Footer Then
Dim cart As ShoppingCart = ShoppingCart.GetShoppingCart()
e.Row.Cells(3).Text = “Total: ” & cart.GetSubTotal().ToString(”C”)
End If
End Sub

‘ This is the method that responds to the Remove button’s click event
Protected Sub gvShoppingCart_RowCommand(ByVal sender As Object, ByVal e As GridViewCommandEventArgs) Handles gvShoppingCart.RowCommand
If e.CommandName = “Remove” Then
Dim cart As ShoppingCart = ShoppingCart.GetShoppingCart()
Dim productId = Convert.ToInt32(e.CommandArgument)
cart.RemoveItem(productId)
End If

‘ We now have to re-setup the data so that the GridView doesn’t keep displaying the old data
BindData()
End Sub

End Class

#Region “Properties”

Private _items As List(Of CartItem)
Public Property Items() As List(Of CartItem)
Get
Return _items
End Get
Private Set(ByVal value As List(Of CartItem))
_items = value
End Set
End Property

#End Region

#Region “Implementation”

‘ Readonly variables can only be set in initialization or in a constructor
Public Shared ReadOnly Instance As ShoppingCart

Public Shared Function GetShoppingCart() As ShoppingCart
‘ If the cart is not in the session, create one and put it there
If HttpContext.Current.Session(”ASPNETShoppingCart”) Is Nothing Then
Dim cart As New ShoppingCart()
cart.Items = New List(Of CartItem)()
HttpContext.Current.Session(”ASPNETShoppingCart”) = cart
End If

Return (DirectCast(HttpContext.Current.Session(”ASPNETShoppingCart”), ShoppingCart))

End Function

#End Region

#Region “Item Modification Methods”

‘ AddItem() – Adds an item to the shopping
Public Sub AddItem(ByVal productId As Integer)
‘ Create a new item to add to the cart
Dim newItem = New CartItem(productId)

‘ If this item already exists in our list of items, increase the quantity
‘ Otherwise, add the new item to the list
If Items.Contains(newItem) Then
For Each item As CartItem In Items
If item.Equals(newItem) Then
item.Quantity += 1
Return
End If
Next
Else
newItem.Quantity = 1
Items.Add(newItem)
End If

End Sub

‘ SetItemQuantity() – Changes the quantity of an item in the cart
Public Sub SetItemQuantity(ByVal productId As Integer, ByVal quantity As Integer)
‘ If we are setting the quantity to 0, remove the item entirely
If quantity = 0 Then
RemoveItem(productId)
Return
End If

‘ Find the item and update the quantity
Dim updatedItem = New CartItem(productId)
For Each item As CartItem In Items
If item.Equals(updatedItem) Then
item.Quantity = quantity
Return
End If
Next
End Sub

‘ RemoveItem() – Removes an item from the shopping cart
Public Sub RemoveItem(ByVal productId As Integer)
Dim removedItem = New CartItem(productId)

For Each item As CartItem In Items
If item.Equals(removedItem) Then
Items.Remove(item)
Return
End If
Next
End Sub

#End Region

#Region “Reporting Methods”

‘ GetSubTotal() – returns the total price of all of the items before tax, shipping, etc.
Public Function GetSubTotal() As Decimal
Dim subTotal As Decimal = 0
For Each item As CartItem In Items
subTotal += item.TotalPrice
Next

Return subTotal
End Function

#End Region

End Class

Partial Class _Default
Inherits System.Web.UI.Page

Protected Sub btnAddShoes_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnAddShirt.Click
‘ Add product 1 to the shopping cart
Dim cart As ShoppingCart = ShoppingCart.GetShoppingCart()
cart.AddItem(1)

‘ Redirect the user to view their shopping cart
Response.Redirect(”ViewCart.aspx”)
End Sub

Protected Sub btnAddShirt_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnAddShorts.Click
Dim cart As ShoppingCart = ShoppingCart.GetShoppingCart()
cart.AddItem(2)
Response.Redirect(”ViewCart.aspx”)
End Sub

Protected Sub btnAddPants_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnAddShoes.Click
Dim cart As ShoppingCart = ShoppingCart.GetShoppingCart()
cart.AddItem(3)
Response.Redirect(”ViewCart.aspx”)
End Sub
End Class

‘ The ShoppingCart class
‘ Holds the items that are in the cart and provides methods for their manipulation
Public Class ShoppingCart

#Region “Properties”

Private _items As List(Of CartItem)
Public Property Items() As List(Of CartItem)
Get
Return _items
End Get
Private Set(ByVal value As List(Of CartItem))
_items = value
End Set
End Property

#End Region

#Region “Implementation”

‘ Readonly variables can only be set in initialization or in a constructor
Public Shared ReadOnly Instance As ShoppingCart

Public Shared Function GetShoppingCart() As ShoppingCart
‘ If the cart is not in the session, create one and put it there
If HttpContext.Current.Session(”ASPNETShoppingCart”) Is Nothing Then
Dim cart As New ShoppingCart()
cart.Items = New List(Of CartItem)()
HttpContext.Current.Session(”ASPNETShoppingCart”) = cart
End If

Return (DirectCast(HttpContext.Current.Session(”ASPNETShoppingCart”), ShoppingCart))

End Function

#End Region

#Region “Item Modification Methods”

‘ AddItem() – Adds an item to the shopping
Public Sub AddItem(ByVal productId As Integer)
‘ Create a new item to add to the cart
Dim newItem = New CartItem(productId)

‘ If this item already exists in our list of items, increase the quantity
‘ Otherwise, add the new item to the list
If Items.Contains(newItem) Then
For Each item As CartItem In Items
If item.Equals(newItem) Then
item.Quantity += 1
Return
End If
Next
Else
newItem.Quantity = 1
Items.Add(newItem)
End If

End Sub

‘ SetItemQuantity() – Changes the quantity of an item in the cart
Public Sub SetItemQuantity(ByVal productId As Integer, ByVal quantity As Integer)
‘ If we are setting the quantity to 0, remove the item entirely
If quantity = 0 Then
RemoveItem(productId)
Return
End If

‘ Find the item and update the quantity
Dim updatedItem = New CartItem(productId)
For Each item As CartItem In Items
If item.Equals(updatedItem) Then
item.Quantity = quantity
Return
End If
Next
End Sub

‘ RemoveItem() – Removes an item from the shopping cart
Public Sub RemoveItem(ByVal productId As Integer)
Dim removedItem = New CartItem(productId)

For Each item As CartItem In Items
If item.Equals(removedItem) Then
Items.Remove(item)
Return
End If
Next
End Sub

#End Region

#Region “Reporting Methods”

‘ GetSubTotal() – returns the total price of all of the items before tax, shipping, etc.
Public Function GetSubTotal() As Decimal
Dim subTotal As Decimal = 0
For Each item As CartItem In Items
subTotal += item.TotalPrice
Next

Return subTotal
End Function

#End Region

End Class

using System;

public partial class _Default : System.Web.UI.Page {
protected void Page_Load(object sender, EventArgs e) {

}

protected void btnAddShoes_Click(object sender, EventArgs e) {
// Add product 1 to the shopping cart
ShoppingCart cart = ShoppingCart.GetShoppingCart();
cart.AddItem(1);
// Redirect the user to view their shopping cart
Response.Redirect(”ViewCart.aspx”);
}

protected void btnAddShirt_Click(object sender, EventArgs e) {
ShoppingCart cart = ShoppingCart.GetShoppingCart();
cart.AddItem(2);
Response.Redirect(”ViewCart.aspx”);
}

protected void btnAddPants_Click(object sender, EventArgs e) {
ShoppingCart cart = ShoppingCart.GetShoppingCart();
cart.AddItem(3);
Response.Redirect(”ViewCart.aspx”);
}

}

using System;
using System.Web.UI.WebControls;
/*************************** MEASURE LINE *****************************************/
public partial class ViewCart : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
// ASP.NET keeps track of the state of all server controls
// (like the GridView). Because of this, we don’t need to supply it with
// the data every time the page loads. (No more re-checking checkboxes
// that were checked or re-selecting the right item in the drop-down when
// the page is submitted. It’s all done for you!)
if (!IsPostBack)
BindData();
}

protected void BindData()
{
// Let’s give the data to the GridView and let it work!
// The GridView will take our cart items one by one and use the properties
// that we declared as column names (DataFields)
ShoppingCart cart = ShoppingCart.GetShoppingCart();
gvShoppingCart.DataSource = cart.Items;
gvShoppingCart.DataBind();
}

protected void gvShoppingCart_RowDataBound(object sender, GridViewRowEventArgs e) {
// If we are binding the footer row, let’s add in our total

if (e.Row.RowType == DataControlRowType.Footer) {
ShoppingCart cart = ShoppingCart.GetShoppingCart();
e.Row.Cells[3].Text = “Total: ” + cart.GetSubTotal().ToString(”C”);
}
}

/**
* This is the method that responds to the Remove button’s click event
*/
protected void gvShoppingCart_RowCommand(object sender, GridViewCommandEventArgs e) {
if (e.CommandName == “Remove”) {
int productId = Convert.ToInt32(e.CommandArgument);
ShoppingCart cart = ShoppingCart.GetShoppingCart();
cart.RemoveItem(productId);
}

// We now have to re-setup the data so that the GridView doesn’t keep
// displaying the old data
BindData();
}

protected void btnUpdateCart_Click(object sender, EventArgs e) {
foreach (GridViewRow row in gvShoppingCart.Rows) {
if (row.RowType == DataControlRowType.DataRow) {
// We’ll use a try catch block in case something other than a number is typed in
// If so, we’ll just ignore it.
try {
// Get the productId from the GridView’s datakeys
int productId = Convert.ToInt32(gvShoppingCart.DataKeys[row.RowIndex].Value);
// Find the quantity TextBox and retrieve the value
int quantity = int.Parse(((TextBox)row.Cells[1].FindControl(”txtQuantity”)).Text);
ShoppingCart cart = ShoppingCart.GetShoppingCart();
cart.SetItemQuantity(productId, quantity);
} catch (FormatException) { }
}
}

BindData();
}
}

Thanks for great tut.

Thanks , is really good

I need to show a produt list with : Id, Name, Price, Graph, and description , do you have some samples ?

Regards