.net - ASP.NET Shopping Cart?
Feb 7, 2011
I am in the middle of building a very simple shopping cart in asp.net with a VB backend but I am running into problems with my code. When I run my application and try to add a product to the cart I get an error message.
Object reference not set to an instance of an object. 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.NullReferenceException: Object reference not set to an instance of an object.
Source Error:
Line 27: Dim blnMatch As Boolean = False
Line 28:
Line 29: For Each Me.objDR In objDT.Rows
Line 30: If objDR("StockItemName") = Product Then
Line 31: objDR("Quantity") += txtQuantity.Text
I am not sure why it is doing this and was hoping that perhaps someone could take a look and offer up some advice? I have checked over my code and I cannot find anything wrong however I would take any guidence that you may have on it.
[Code]...
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Mar 3, 2008
I am trying to create a shopping cart in Visual Basic. I have most of it figured out. However, when I click the Add Cart button, the item will add; however, when I add a new item, it will not go to the next line to display it. It instead replaces the first item I added. For example if the user chooses 1111 for the part number and qty is 2 then clicks the Add to Cart button, the following will show in a group box below: 1111 Alarm Clock 2 $19.95 $39.90
If the person wants to add part number 2222 and qty is 2, that relating info should show up below the first entry of the Alarm clock. In my code, it's not doing that, it's just replacing the first line (alarm clock entry). However, it is keeping track of the total amount added to the cart.
Here is my code that I have done for the Add Cart button:
Private Sub xAddButton_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles xAddButton.Click
Dim searchFor As String
[Code]......
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Jul 28, 2011
I am building a shop (without payment)
i.e.
1) Select Products
2) Checkout
3) Confirmation
The selecting products screen will look like a gridview which will display.
name price quantity
Text Text Input box
So i.e. lets say I have 10 products per page so i.e. 10 quantity input boxes per gridview. And then I have 2 Buttons below my gridview i.e. Update and Checkout. Just even worrying about Update for now. How could that work i.e. would I have to check every input box in gridview for which a value was entered ?
I.e. is there any example how I can loop through gridview row check for a value which is greater than 0 or null for example and if there is a value then perform a function like [Code]
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Dec 4, 2011
I've created a program that pulls item prices from a database. The problem I'm having right now is that I'd like to display a running total, as the program currently only displays the list of items and their prices.
Private Sub btnGoToCart_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnGoCart.Click
Me.Hide()
[Code].....
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Apr 30, 2010
I am working on a class project and I am trying to create a shopping cart application. I need to transfer info from listboxes on 2 forms to the main form and calculate the charges for "the books." I am having a hard time writing the code to properly transfer the items and I really have no idea where to start with the calculating the charges for subtotals of the selected books.
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Dec 27, 2011
My project is to create a shopping cart application. I have my main form and from there the user can go to two different forms to add books to their cart, the cart being the main form. This all works. What I can't figure out, is how to use global variables for the prices, shipping, tax and updating the total. I have places for this information to show up on the main form, and I've created a module for the calculations and prices, but I don't know how to code it to get the prices to show up in the specified areas.
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Nov 14, 2011
How can I get the items in my code from my listbox which is called "selectListBox" to a shopping cart called "cartlistbox", when the add button is clicked?
Public Class MainForm
Private Sub MainForm_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
[Code].....
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Dec 1, 2011
Using following method to create Shopping Cart Session [URL]Now running locally on my machine where sessionstate mode is inProc by default, all seems to perform fine.I'm writing an application which I've just placed up on hosting provider (shared hosting environment etc). Their default sessionstate is stateserver so I had to serialise the classes to fit in with this. It's using cookies.The basket (adding,removing etc) works fine but I'm seeing some odd things happen regarding the persistency of the session.
On my local machine, if I access the site in 2 separate browsers, if I add items in IE, I can see them in Firefox when I refresh. This doesn't make any sense to me since cookies are per browser.Plus I thought that when a session was generated, its id would be unique so there is no way that one user should be able to see anothers session data (unless tabbed in same browser perhaps)Even worse, if I start adding/removing items in IE and doing likewise in Firefox, both of them show very random cart results every time you refresh the browser.
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Mar 20, 2012
Note: This code actually codes from a tutorial book I'm reading at the moment, so you can imagine this is frustrating me greatly! I'm building a basic shopping cart, using VB.NET 4, Visual Studio 2010 and MS SQL Server R2 2008. The code below is supposed to remove items from the cart, by reading a session variable, editing it to remove the appropriate ProductID and return the amending string to the session variable. It is then supposed to rebind the data to the gridview (gvCart) to refresh the data...but it seems here there is an error.
Every time I build the site in Visual Studio, it validates fine. But every time I run the site, and attempt to use the remove button it gives me the error:Incorrect syntax near ')'.ith the IDE pointing me toward the final parenthesis
Protected Sub gvCart_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles gvCart.SelectedIndexChanged
'This method is hooked to the Remove button & is removing items from the cart
[code].....
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Aug 5, 2011
I have a gridview as follows
<asp:GridView ID="productListTable" runat="server" DataSourceID="srcProductListPerCustomer" AutoGenerateColumns="False" AlternatingRowStyle-CssClass="tr_dark" HeaderStyle-CssClass="header_req"
[Code]....
And it actually seems to work on first instance (altho im not sure the above is a good way to do it, but the problem is when use the pagination on the gridview I get the error
Index was out of range. Must be non-negative and less than the size of the collection. Parameter name: index
On the line
Dim productId As String = productListTable.DataKeys(i).Value
why I am getting this error and also is there a better way to do it ?
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Apr 26, 2012
i havent had problems in visual basic all the ay up to this point. I have been given a shopping cart program that I must use: a MainForm, MP3From, AlbumForm, and a module
I finally got my program to send data from the listbox on my MP3Form to the listbox on my MainForm but something isnt right still. I need to be able to click an an item from the lstMP3(listbox on MP3Form) to lstShoppingCart(listbox on MainForm) multiple times without having to close the MP3Form everytime to add the items to lstShoppingCart. Here is what I got so far on my MainForm:
[code...]
This assignment makes me mad cause we have not even covered half the stuff I am having to use in this form at all this semester. If i can get a little explanation on instantiate, inheritance, and declaring and object variable and how its used to transfer data from one to the other.
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May 1, 2012
I am working on a project for a class, and am having trouble getting my program to automatically calculate the subtotal every time an item is added to the shopping cart list. I've tried sub procedures and functions, but I can't seem to get it to work.
[Code]...
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Feb 26, 2012
For the past couple weeks I've been tormented by this problem: I am trying to make a program that will go to a specific web site and add things to my cart on that page. I can get the program to go to the page, log into my account, and get to the right product. But, I can't figure out how to click on the ADD TO CART image.
Also, each product page has the main product, with an ADD TO CART image, and at other places on the screen there are other products shown, each with its own ADD TO CART image.I have been examining the source for the pages and here are a couple examples:
[Code]...
How can I click on one of those addToCart.gif images? It looks like they do not have names or IDs for me to refer to them with?
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Apr 7, 2011
I have create a shopping cart in vb.net, so far i can add items to cart but cant empty or remove items from cart. this is the code I have so far:-
<asp:Content ID="Content2" ContentPlaceHolderID="MainContent" Runat="Server">
<div id="mycart">
<br />
[code]....
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Jun 12, 2011
i am developing an online shopping site..so when the user adds any item to the cart i store it in a table...now what i want is to count the number of items in the cart as well as update the number of items in cart every time the user adds a new item....
Public Function AddToCart(ByVal itemID As String, ByVal itemName As String, ByVal itemPrice As Integer, _
ByVal offer As String, ByVal buyNo As String, ByVal userID As String) As String
Dim sqlStatement As String = "INSERT INTO shoppingCart" & _
[code].....
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Nov 11, 2011
I'm trying to get my items to show up in my shopping card but nothing shows up
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Mar 28, 2009
I am in the process of developing a Recipe Manager for myself. It will allow me or the user to add and manage their recipes, create, save, and print shopping lists and daily menus. My question is, what is the best way to save the user's recipes, shopping lists, and menus? I've thought of text files, and databases but they just don't seem right for the job.
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Jan 25, 2012
The user can select from either print or audio books and add to the shopping cart. The list box shows all items in the shopping cart. There is a 6%. sales tax on the total cost of the items in the shopping cart and a 2 dollars shipping charge per item in the shopping cart. to remove an item from the shopping cart, the user selects it in the list box and clicks the remove button. the subtotal, tax, shipping, an total fields should be adjusted accordingly.
To add one of the items in the list to the shopping cart, the user selects it and clicks the add book to cart button. to cancel the operation, the user clicks the cancel button. I am using a standard module to declare global variables. My file is attach I have the problem that everytime I add a new item, it will just add 2 and then I add another item and it add 2 it does not show the subtotal or the tax and shipping and the real total....
Module PriceCalcModule
'constants for Print
Public Const g_decDID_YOU_KNOW As Decimal = 11.95
Public Const g_decHISTORY_SCOTLAND As Decimal = 14.5
Public Const g_decLEARN_CALC As Decimal = 29.95
Public Const g_decFEEL_STRESS As Decimal = 18.5
[Code] .....
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Feb 10, 2012
i have problem on use HttpWebRequest with "POST" method.First, I access this link [URL] and go to the cart page.Then when I change the quantity to 2, I had see the live http header to use "POST" and submit the content to the server.I follow the header and write with vb2008, but I get the server return 503 error on the code that getting response,?
Here is my
Dim logincookie As CookieContainer
Dim response As HttpWebResponse
Dim tempCookies As New Cookie
Dim req As HttpWebRequest
[code]....
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