i got problems with my class file. most of the errors saying that 'Object reference not set to an instance of an object'. it looks like all functions in class file cannot be performed, even i do declare the class at code-behind file. do i have to call the class file in .aspx page? like this <%# Imports ... %>. this is page for CheckOut.aspx.vb.

Partial Class Checkout_CheckOut
Inherits System.Web.UI.Page

Private order As Order
Private cust As Customer
Private cart As ShoppingCart

Protected Sub Page\_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load

    cart = Session("cart")

    If Session("order") Is Nothing Then
        order = New Order(DateTime.Now, Nothing, Session("cart"))
        Session("order") = order
    Else
        order = Session("order")
        cart = order.Cart
    End If

    cust = New Customer(txtEmail.Text, txtLastName.Text, txtFirstName.Text, \_
        txtAddress.Text, txtCity.Text, txtState.Text, txtPostCode.Text, txtPhone.Text, \_
        txtEmail.Text)
    order.Cust = cust

    lblSubtotal.Text = order.SubTotal.ToString("c")
    lblShipping.Text = order.Shipping.ToString("c")
    lblTotal.Text = order.Total.ToString("c")
End Sub

Protected Sub Wizard1\_FinishButtonClick(ByVal sender As Object, ByVal e As  \_
    System.Web.UI.WebControls.WizardNavigationEventArgs) Handles Wizard1.FinishButtonClick

    ' process credit card information here
    Dim success As Boolean
    success = OrderDB.WriteOrder(order)      'the function WriteOrder from OrderDB class 
    Session("cart") = Nothing                'can't be performed
    Session("order") = Nothing
    If success Then
        Response.Redirect("Confirmation.aspx")
    Else
        Response.Redirect("Confirmation.aspx?Error=1")
    End If
End Sub

End Class

If i use binary data type for image, did i have to upload the image to DB? Is it a must to use upload function with generic handler? if i use upload function, does this means i need to upload images in separate table? i want to put images in my Products table, with all products' details. can i just put image path in DB and display the images in DataList? I need to display images for products, the details and the prices dynamically in repeated columns. I did the handler, but the image didn't appear, just the details appeared. I wonder so hard what's wrong with this. Is it my SqlDataSource or my handler?

I use datatype varchar for image (put image path) and display in gridview, this is fine. But when i use the same datatype and display in datalist, the image didn't appear, but the description and price for the product appear. If i use binary for image, then i need to upload the picture to DB, rite? and also use generic handler. what is the easier way to display image for product and the details from different product categories (it's like e-commerce application)?

How can i develop a product catalog that diplay a large picture of product and put the description with price under the picture? I use DataList, but the pictures don't appear. Is it true, if i use image handler, my data type for image must be in binary? My current data type for image now is varchar. <asp:DataList id="dlstImages" RepeatColumns="3" runat="server"> <ItemTemplate> <asp:Image ID="Image1" ImageUrl='<%# Eval("Name", "~/UploadImages/{0}") %>' style="width:200px" Runat="server" /> <br /> <%# Eval("Name") %> </ItemTemplate> </asp:DataList>

And this is code for Order.aspx. Incorrect syntax that I can't find. That makes me really worried!

<%@ Page Language="VB" MasterPageFile="~/MasterPage.master" Title="Untitled Page" AutoEventWireup="False" %>
<%@ Register Src="~/Manage/Order.ascx" TagName="Order" TagPrefix="uc1" %>

<script runat="server">

Protected Sub Page\_Load(ByVal sender As Object, ByVal e As System.EventArgs)
    If Not IsPostBack Then
        ddlOrder.DataBind()
    End If
    Session("OrderNum") = ddlOrder.SelectedValue
End Sub

</script>

<asp:Content ID="Content1" ContentPlaceHolderID="head" Runat="Server">
</asp:Content>
<asp:Content ID="Content2" ContentPlaceHolderID="ContentPlaceHolder1" Runat="Server">
Choose an order to display:
<asp:DropDownList ID="ddlOrder" runat="server" AutoPostBack="True"
DataSourceID="SqlDataSource1" DataTextField="OrderNum"
DataValueField="OrderNum">
</asp:DropDownList> 
<asp:LinkButton ID="LinkButton1" runat="server"
PostBackUrl="~/Manage/PrintOrder.aspx">Print this page</asp:LinkButton>
<asp:SqlDataSource ID="SqlDataSource1" runat="server"
ConnectionString="<%$ ConnectionStrings:ProjectConnectionString %>"
SelectCommand="SELECT OrderNum FROM Order ORDER BY OrderNum">
</asp:SqlDataSource><br /><br />
<uc1:Order ID="Order1" runat="server" />
</asp:Content>

I'm using Web User Control for Order.aspx file. This is SQL code for Order.ascx.

<asp:SqlDataSource ID="SqlDataSource1" runat="server"
ConnectionString="<%$ ConnectionStrings:ProjectConnectionString %>"
SelectCommand="SELECT Order.OrderNum, Order.OrderDate, Order.CustEmail, Order.Subtotal, Order.Shipping, Order.Total,
Customers.LastName, Customers.FirstName, Customers.Address, Customers.City, Customers.State, Customers.PostCode, Customers.Phone, Customers.Country
FROM Order
INNER JOIN Customers
ON Order.CustEmail=Customers.Email
WHERE Order.OrderNum=@OrderNum
ORDER BY Order.OrderNum">
<SelectParameters>
<asp:SessionParameter Name="OrderNum" SessionField="OrderNum" Type="Int32" />
</SelectParameters>
</asp:SqlDataSource>

<asp:SqlDataSource ID="SqlDataSource2" runat="server"
ConnectionString="<%$ ConnectionStrings:ProjectConnectionString %>"
SelectCommand="SELECT [ProductId], [Name], [Price], [Quantity], [Total], [OrderNum]
FROM [OrderItems]
WHERE ([OrderNum]=@OrderNum)
ORDER BY [ProductId]">
<SelectParameters>
<asp:ControlParameter Name="OrderNum" ControlID="FormView1"
PropertyName="SelectedValue" Type="Int32" />
</SelectParameters>
</asp:SqlDataSource>

What does it means by OP? does this error looks complex? i hope it is not since i'm a beginner. i will post the codes and hope all of you will help.

I've checked many times for the incorrect syntax. But couldn't find any. There's no given location for the specific error. Here is the error and Stack Trace given when I run the appliication.

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.Data.SqlClient.SqlException: Incorrect syntax near the keyword 'Order'.

Stack Trace:

[SqlException (0x80131904): Incorrect syntax near the keyword 'Order'.]
System.Data.SqlClient.SqlConnection.OnError(SqlException exception, Boolean breakConnection) +925466
System.Data.SqlClient.SqlInternalConnection.OnError(SqlException exception, Boolean breakConnection) +800118
System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning(TdsParserStateObject stateObj) +186
System.Data.SqlClient.TdsParser.Run(RunBehavior runBehavior, SqlCommand cmdHandler, SqlDataReader dataStream, BulkCopySimpleResultSet bulkCopyHandler, TdsParserStateObject stateObj) +1932
System.Data.SqlClient.SqlDataReader.ConsumeMetaData() +31
System.Data.SqlClient.SqlDataReader.get_MetaData() +62
System.Data.SqlClient.SqlCommand.FinishExecuteReader(SqlDataReader ds, RunBehavior runBehavior, String resetOptionsString) +297
System.Data.SqlClient.SqlCommand.RunExecuteReaderTds(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, Boolean async) +1005
System.Data.SqlClient.SqlCommand.RunExecuteReader(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, String method, DbAsyncResult result) +132
System.Data.SqlClient.SqlCommand.RunExecuteReader(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, String method) +32
System.Data.SqlClient.SqlCommand.ExecuteReader(CommandBehavior behavior, String method) +122
System.Data.SqlClient.SqlCommand.ExecuteDbDataReader(CommandBehavior behavior) +12
System.Data.Common.DbCommand.System.Data.IDbCommand.ExecuteReader(CommandBehavior behavior) +7
System.Data.Common.DbDataAdapter.FillInternal(DataSet dataset, DataTable[] datatables, Int32 startRecord, Int32 maxRecords, String srcTable, IDbCommand command, CommandBehavior behavior) +141
System.Data.Common.DbDataAdapter.Fill(DataSet dataSet, Int32 startRecord, Int32 maxRecords, String srcTable, IDbCommand command, CommandBehavior behavior) +137
System.Data.Common.DbDataAdapter.Fill(DataSet dataSet, String srcTable) +83
Syst

this is the function in ShoppingCart class.

Imports Microsoft.VisualBasic
Imports System.Collections.Generic

Public Class ShoppingCart

Private \_cart As List(Of CartItem)

Public Sub New()
    \_cart = New List(Of CartItem)()
End Sub

Public Function GetItems() As List(Of CartItem)
    Return \_cart
End Function

Public Sub AddItem(ByVal id As String, ByVal name As String, ByVal price As Decimal)
    Dim itemFound As Boolean = False
    For Each Item As CartItem In \_cart
        If Item.ID = id Then
            Item.Quantity += 1
            itemFound = True
        End If
    Next
    If Not itemFound Then
        Dim item As CartItem
        item = New CartItem(id, name, price, 1)
        \_cart.Add(item)
    End If
End Sub

Public Sub UpdateQuantity(ByVal index As Integer, ByVal quantity As Integer)    'update quantity function
    Dim item As CartItem
    item = \_cart(index)
    item.Quantity = quantity
End Sub

Public Sub DeleteItem(ByVal index As Integer) 'delete item function
    \_cart.RemoveAt(index)
End Sub

Public ReadOnly Property Count() As Integer
    Get
        Return \_cart.Count
    End Get
End Property

End Class

That function is in ShoppingClass class.

I'm developing an e-commerce web-based system & have problem in Shopping Cart part. i.e. update quantity & delete item from cart. This is code-behind for my Cart.aspx. <pre> 'other code above Protected Sub GridView1_RowDeleting(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.GridViewDeleteEventArgs) Handles GridView1.RowDeleting cart.DeleteItem(e.RowIndex) 'error here GridView1.DataBind() End Sub Protected Sub GridView1_RowEditing(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.GridViewEditEventArgs) Handles GridView1.RowEditing GridView1.EditIndex = e.NewEditIndex GridView1.DataBind() End Sub Protected Sub GridView1_RowUpdating(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.GridViewUpdateEventArgs) Handles GridView1.RowUpdating Dim cell As DataControlFieldCell cell = GridView1.Rows(e.RowIndex).Controls(3) Dim t As TextBox = cell.Controls(0) Try Dim q As Integer q = Integer.Parse(t.Text) cart.UpdateQuantity(e.RowIndex, q) 'error here Catch ex As FormatException e.Cancel = True End Try GridView1.EditIndex = -1 GridView1.DataBind() End Sub Protected Sub GridView1_RowCancelingEdit(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.GridViewCancelEditEventArgs) Handles GridView1.RowCancelingEdit e.Cancel = True GridView1.EditIndex = -1 GridView1.DataBind() End Sub 'other code below </pre> The error saying that: Exception Details: System.NullReferenceException: Object reference not set to an instance of an object. Thanks for your help!